Arteriovenous Haemangioma in Two Dogs and a Cat- These are rare tumors with differentiation into arterioles, venules and capillaries.  All have VWF + endothelium and Smooth muscle Actin + tunica media.

Malakoplakia in the Urinary Bladder of a Kitten — Malakoplakia is a form of chronic granulomatous inflammation that in humans most commonly affects the urinary bladder of middle-aged women, it is rare in animals.  Gross lesions included a markedly enlarged bladder with a diffusely nodular mucosal surface. Microscopically, there was diffuse submucosal infiltration by histiocytes stained positively by periodic acid Schiff (PAS) and described in the human condition as ‘‘von Hansemann cells’’. Intracellular and extracellular ‘‘Michaelise Gutman’’ inclusion bodies were seen on light and electron microscopical examination. These structures are considered pathognomonic for malakoplakia.

Bone Marrow Pathology in Dogs and Cats with Non-Regenerative Immune-Mediated Haemolytic Anaemia and Pure Red Cell Aplasia: Non-regenerative IMHA in dogs and cats has been associated with pure red cell aplasia, erythroid maturation arrest or bone marrow erythroid hyperplasia. PRCA and erythroid maturation arrest may result from immune-mediated destruction of erythroid precursor cells within the bone marrow. However, IMHA due to erythroid hyperplasia could be due to variety of pathological changes in bone marrow including dysmyelopoiesis, myelonecrosis,  myelofibrosis, altered vascular permeability/acute inflammation, and hemophagocytic syndrome

Spinal Cryptococcoma in an Immunocompetent Cat (J. Comp. Path. 2008, Vol. 139, 246e251).

Gross lesion: Focal Malacia in the spinal cord. Microscopic lesion: The yeasts were round in shape, 7 mm in diameter and rimmed by a basophilic thin cell wall, which was surrounded by a halo of variable thickness. Narrow-necked budding forms were also present. The parenchymal remnants contained digestion chambers in which Gitter cells, spheroids and myelinic debris were present.

Multiple hepatic vascular cysts in a young ragdoll cat: In cats and dogs, the DDx for congenital intrahepatic cystic structures would include a biliary cyst or pseudocyst, choledochal cysts or cystic duct remnants. For acquired cysts or other cavitated structures, abscesses, parasitic cysts, biliary cyst adenoma, cystadenocarcinoma, cholangiocarcinoma, haemangiosarcoma, and certain metastatic tumours

An Immunohistochemical Study of Feline Endometrial Adenocarcinoma. J. Comp. Path. 2009, Vol. -, 1e6.  Feline endometrial adenocarcinomas are uncommon.  Normal endometria and Neoplastic lesions express pancytokeratins AE1 and AE3, cytokeratin-14, vimentin, a-actin, cyclo-oxygenase-2, E-cadherin, b-catenin, the progesterone receptor, the estrogen receptor and caveolin-1.  Synthesis of cyclo-oxygenase-2 and reduced expression of progesterone receptors may be involved in the neoplastic transformation of feline endometrium. The loss of cellular adhesion that occurs within these tumours does not require down-regulation of E-cadherin expression and nuclear translocation of b-catenin is not a feature of these neoplasms.

Muscular Dystrophy with Reduced β-Sarcoglycan in a Cat. J. Comp. Path. 2009, Vol. -, 1e5.  Sarcoglycans (SGs) are sarcolemmal transmembrane glycoproteins that form a hetero- tetrameric complex known as the sarcoglycan complex (SGC). The SGC is a member of the dystrophin glycoprotein complex, which links actin in the cytoskeleton to the extracellular matrix through α2-laminin, providing protection of the sarcolemma from tension during muscle contraction.  SGC also has a role in intracellular signal transduction.  Muscle biopsy revealed moderate variability in myofiber size, with numerous atrophic rounded fibers, rare myofiber necrosis, regeneration and moderate perimysial and endomysial fibrosis. Immunohistochemistry revealed decreased expression of β- and γ-SG and western blotting revealed markedly decreased β-SG with normal expression of α-, γ- and δ-SG, caveolin-3 and calpain-3.  Not previously known in cats.

Detection of mixed infections with ‘‘Candidatus Mycoplasma haemominutum’’ and Mycoplasma haemofelis using real-time TaqMan polymerase chain reaction. J Vet Diagn Invest 19:250–255 (2007). Hemotropic mycoplasmas (hemoplasmas) are epierythrocytic mycoplasmas that have never been cultured in vitro. At least 3 species infect cats: Mycoplasma haemofelis (Mhf) and ‘Candidatus Mycoplasma haemominutum’ (Mhm), as well as ‘Candidatus Mycoplasma turicensis’ (Mtc), a new species that was recently described in cats in Switzerland. The latter species appears to be present in cats in North America, as well as an organism related to ‘Candidatus M. haematoparvum’ (Mhp), which was first identified in dogs. Mhf is capable of causing severe anemia in cats, whereas Mhm has yet to be associated with disease in immunocompetent cats.

Light-chain multiple myeloma in a cat. J Vet Diagn Invest 19:443–447 (2007).  IN general, the monoclonal immunoglobulin produced in multiple myeloma may be an entire immunoglobulin of any class, a heavy chain only, or a light chain only (light-chain multiple myeloma, also called Bence-Jones myeloma).  In this case, the cat had atypical plasma cell infiltration in the bone marrow, biclonal gammopathy caused by polymerization of myeloma protein (M-protein), and Bence-Jones proteinuria.

Sinonasal plasmacytoma in a cat. J Vet Diagn Invest 19:573–577 (2007). The right nasal cavity and the right frontal sinus were partially occluded by a soft whitish mass. Microscopically, the mass was composed of well-differentiated plasma cells that were

immunopositive for immunoglobulin G and lambda light chains. These findings were consistent with a mature type sinonasal plasmacytoma.

Nocardia tenerifensis genome identification in a cutaneous granuloma of a cat. J Vet Diagn Invest 19:577–580 (2007). subcutaneous mass in its tail. Histologically, this mass consisted of ill-defined pyogranulomas centered around aggregates of gram-positive, acid-fast filamentous bacteria, consistent with Nocardia.

Assessment of melamine and cyanuric acid toxicity in cats. J Vet Diagn Invest 19:616–624 (2007).  Urine and touch impressions of kidneys from all cats dosed with the combination revealed the presence of fan-shaped, birefringent crystals. Histopathologic findings were limited to the kidneys and included crystals primarily within tubules of the distal nephron, severe renal interstitial edema, and hemorrhage at the corticomedullary junction. The kidneys contained estimated melamine concentrations of 496 to 734 mg/kg wet weight and estimated cyanuric acid concentrations of 487 to 690 mg/kg wet weight. The results demonstrate that the combination of melamine and cyanuric acid is responsible for acute renal failure in cats.

Immunohistochemical characterization of a hepatic neuroendocrine carcinoma in a cat.  J Vet Diagn Invest 20:110–114 (2008). yellow-brown, firm, multilobulated tumor was identified in the liver. Microscopically, the mass consisted of neoplastic cells arranged in small, closely packed nests within a thin fibrovascular stroma.  Immunohistochemically, most of the neoplastic cells were immunoreactive for chromogranin A, neuronspecific enolase (NSE), and cytokeratin AE1/AE3 and weakly labeled for synaptophysin. The tumor was negative for glial fibrillary acidic protein (GFAP), vimentin, and cytokeratins.  These tumors initially described in the small intestine of human beings were first named carcinoid. The term neuroendocrine carcinoma is now used for all neuroendocrine tumors, acknowledging that all neuroendocrine tumors are potentially malignant.

A case of coccygeal chondroid chordoma in a cat: morphological and immunohistochemical features. J Vet Diagn Invest 20:679–681 (2008). mass on the tip of the tail. Histological examination performed after apical caudectomy revealed a neoplasm affecting

the distal part of the last coccygeal vertebra. The neoplasm consisted of lobules of physaliferous cells surrounding cartilaginous tissue and a central core of trabecular bone.

Perforin expression in feline epitheliotropic cutaneous lymphoma.  J Vet Diagn Invest 20:831–835 (2008). Granular lymphocytes were consistently detected on blood smears, and histologically, the tumor involved the skin and superficial subcutis. Tumor lymphocytes expressed cluster of differentiation 3 (CD3) andperforin molecules, suggestive of a cytotoxic phenotype. Location, histopathological features, and perforin expression were similar to a distinct entity in human medicine designated primary cutaneous, CD8-positive, epidermotropic, cytotoxic, T-cell lymphoma.

Immunohistochemical features of a feline spinal cord gemistocytic astrocytoma.  J Vet Diagn Invest 20:836–838 (2008). On histologic exanimation, the neoplastic cells were pleomorphic, with distinct cell borders and abundant cytoplasm that frequently extended into variably sized fibrillar processes. Neoplastic cells were strongly positive for GFAP and negative for EGFR. Eight percent (mean percentage) of neoplastic cells were p53 positive.

A nonhealing ulcerative skin lesion associated with Trichinella nativa infection in a cat.  J Vet Diagn Invest 20:839–843 (2008). clinically apparent disease seems to be a rare manifestation of this infection in cats.  This manifested as a firm, poorly circumscribed subcutaneous mass adjacent to the eye, which demonstrated clinical features and histopathologic findings indicative of chronic inflammation associated with granulation tissue and fibrodysplasia.  PCR speciated the organism as trichinella native.

Prevalence and Histopathologic Characteristics of Pancreatitis in Cats. Vet Pathol 44:39–49 (2007).    The lesions of CP in cats resemble CP in humans,with fibrosis being more prominent than inflammatory changes. Cystic degeneration gradually increased.  A distinct nodular change of zymogen  depletion and acinar cell dysplasia not associated with pancreatitis was prominent in 15.6% of the pancreases.  Histologically, AP consisted of neutrophilic inflammation associated with interstitial edema and necrosis of mesenteric fat.

An Immunohistochemical and Polymerase Chain Reaction Evaluation of Feline Plasmacytic Pododermatitis. Vet Pathol 44:80–83 (2007). Mycobacterium bovis. Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, Chlamydophila felis, Mycoplasma spp., Toxoplasma gondii, and feline herpesvirus 1 (FHV-1) were negative.

A Clinicopathological Study of 52 Feline Epulides.  Vet Pathol 44:161–169 (2007). Fibromatous (57.7%) , giant cell epulis (28.8%)  , acanthomatous (7.7%), ossifying 5.8%). Giant cell epulides presented significant differences in clinical behavior compared with the fibromatous type, including rapid growth, presence of ulcerative changes, and rapid recurrence after surgery.  Extensive ulceration and inflammation results in increased osteoclastic activity. The osteoclast-like giant cells are most likely formed from a monocyte/ macrophage-like osteoclast precursor that differentiates into osteoclasts under the influence of mononuclear osteoblast-like stromal cells.

Fatal Streptococcus canis Infections in Intensively Housed Shelter Cats.  Vet Pathol 44:218–221 (2007).   1. skin ulceration and chronic respiratory infectionthat progressed, in some cats, to necrotizing sinusitis and meningitis.  2. progression from necrotizing fasciitis with skin ulceration to toxic shock–like syndrome, sepsis, and death. S canis was the sole pathogen identified in most cases.

Distribution of Lesions and Antigen of Highly Pathogenic Avian Influenza Virus A/Swan/Germany/R65/06 (H5N1) in Domestic Cats after Presumptive Infection by Wild Birds.  Vet Pathol 44:261–268 (2007). Histologically, the main findings associated with influenza in all cats were bronchointerstitial pneumonia and marked random hepatic necrosis. In addition, all animals displayed lymphoid necrosis in the spleen and Peyer’s patches and necrosis of the adrenal cortex.  Immunohistochemically, nucleoprotein of HPAIV was present  intralesionally in the lungs, liver, adrenal glands, and lymphoid tissues. Incidental finding- granulomatous pneumonia caused by Aelurostrongylus sp.

Diagnoses and Clinical Outcomes Associated with Surgically Amputated Feline Digits Submitted to Multiple Veterinary Diagnostic Laboratories. Vet Pathol 44:362–365 (2007). Squamous cell carcinoma was the most commonly identified malignant tumor (n 5 15; 23.8%) and was associated with a median survival time of 73 days. Other diagnoses included fibrosarcoma (n 5 14; 22.2%); adenocarcinoma, likely metastases of a primary pulmonary neoplasm (n 5 13; 20.6%); osteosarcoma (n 5 5; 7.9%); mast cell tumor (n 5 4; 6.3%); hemangiosarcoma (n 5 5; 7.9%); malignant fibrous histiocytoma (n 5 2; 3.2%); giant cell tumor of bone (n 5 2; 3.2%); and hemangioma (n 5 2; 3.2%). Giant cell tumor of bone has not been previously described in the digits of cats.

Endometrial Stromal Sarcoma with Smooth Muscle and Glandular Differentiation of the Feline Uterus.  Vet Pathol 44:379–382 (2007). The tumor showed a proliferation of both endometrial stromal and smooth muscle cells accompanied by prominent vasculature. There were well-differentiated endometrial glands, and tubuli made up a monolayer of eosinophilic cuboidal epithelium. Immunohistochemically, the spindle-shaped cells and half of the stromal-like cells reacted to caldesmon and desmin antibodies. The neoplastic epithelium expressed AE1/AE3 cytokeratin.

Interstitial Cell Tumor and Sertoli Cell Tumor in the Testis of a Cat.  Vet Pathol 44:394–397 (2007). The presence of penile papillae implied testosteroneproduction. Testes were not palpable, but the left testis was found in the scrotum by surgical exploration and was mostly replaced by the 2 tumors. The interstitial cell tumor, but not the Sertoli cell tumor, was immunohistochemically positive for Melan-A, consistent with steroid production.

Mycobacterium fortuitum Pneumonia in a Cat and the Role of Lipid in the Pathogenesis of Atypical Mycobacterial Infections.  Vet Pathol 44:543–546 (2007).  Mycobacterium fortuitum is a nontuberculous, and nonlepromatous mycobacterium that can cause infections in animals and humans. In dogs and cats, it is one of the most common agents of ulcerative dermatitides and panniculitides caused by atypical mycobacteria.  IN this case the pneumonia resembled lipoid pneumonia in humans.  We discuss the role of lipids in the pathogenesis of mycobacterioses and suggest an association between atypical mycobacteria and lipid-rich environments.

Cutaneous Toxoplasmosis in a Female Japanese Cat. Vet Pathol 44:683–687 (2007). Necrotizing granulomatous panniculitis, vasculitis, and mastitis, and contained free and clustered protozoal organisms. The organism was present in the cytoplasm of macrophages, fibroblasts, endothelial cells, and mammarygland epithelia. The organism was positive for anti-Toxoplasma gondii and anti-Neospora caninum antibodies. Electron microscopy showed single and grouped tachyzoites, with morphologic features similar to those of T. gondii. Polymerase chain reaction and deoxyribonucleic acid sequence analysis was consistent with T. gondii infection.

Naturally Occurring Parvovirus-associated Feline Hypogranular Cerebellar Hypoplasia—A Comparison to Experimentally-induced Lesions Using Immunohistology. Vet Pathol 44:831–841 (2007).  In type 1 lesions, the cortex was nearly agranular, with an extremely thin molecular layer; the Purkinje cells were randomly placed and oriented, and their stunted main dendrite produced a thorn-covered atrophic dendritic tree; the basket cell axons ran randomly and had dysmorphic endings; and myelinated fibers were severely reduced in folia axes. In type 2 lesions, the cortex was hypogranular; the Purkinje cells were linearly organized, but their main dendrite extended too far in the molecular layer before giving up smooth, bent secondary dendrites; many basket cells were located along the cerebellar surface, and their axons ran at right angle to the surface; myelinated fibers were moderately reduced. Defects in climbing fiber synapse translocation and elimination were evident in both types of lesion.  viral NS1 protein  cytotoxicity might explain degenerative changes in the Purkinje cells that were present, in addition to the development defect.

Mammary Invasive Micropapillary Carcinoma in Cats: Clinicopathologic Features and Nuclear DNA Content. Vet Pathol 44:842–848 (2007). Invasive micropapillary carcinoma (IMC) is a variant of infiltrating ductal carcinoma of the breast associated with poor outcome.  IMC’s have features of high biologicaggressiveness and should be classified as independent histologic types of FMC.

Nasal and Nasopharyngeal Lymphoma in Cats: 50 Cases (1989–2005). Vet Pathol 44:885–892 (2007). Lymphoma is the most common nasal cavity tumor in cats. Histologically, all were considered diffuse lymphoid neoplasms and no cats displayed features of follicular lymphoma.  32 were uniformly positive for CD79a, 7 were uniformly CD3 positive, and 6 had a mixed population of CD79a and CD3 cells. Epithelioptropism was exhibited in 4 of 5 (80%) cats in which there was sufficient epithelium present for evaluation.  The most common biochemical abnormalities were panhyperproteinemia in 26/46 (57%) of cats and hypocholesterolemiain 11/46 (24%) of cats.

Leukoencephalomyelopathy in Specific Pathogen-free Cats. Vet Pathol 44:912–916 (2007). bilateral axonal degeneration within white matter regions of the cervical, thoracic, and lumbar spinal cord and in the white matter of the cerebral internal capsule and peduncle, in the roof of the fourth ventricle and inferior cerebellar peduncle, and in the external arcuate and pyramidal fibres of the medulla. There were varying degrees of accompanying microgliosis, astrocytosis, and capillary hyperplasia.

Feline Cutaneous Viral Papilloma Associated with Human Papillomavirus Type 9. Vet Pathol 44:924–927 (2007).  multinodular exophytic mass on the dorsal surface of the nose. Histologic examination revealed hyperkeratosis, epidermal hyperplasia, papillomatosis, koilocytosis, and possible intranuclear viral inclusions. Polymerase chain reaction amplified papillomaviral deoxyribonucleic acid from formalin-fixed samples of the lesion. Sequencing of the amplicon revealed 98% similarity to human papillomavirus (HPV) type 9.

Congenital Unilateral Absence of the Corticospinal Tract in a Siamese Cat.  Vet Pathol 44:949–951 (2007). Pathologic investigation revealed unilateral (right-sided) absence of the corticospinal (pyramidal) tract throughout its normal course. Although an infectious cause cannot be completely ruled out a genetic etiology was suspected.

B-Cell Lymphoma in the Peripheral Nerves of a Cat Vet Path 2008 Jan: B-cell (Burkitt-type lymphoma) diffusely infiltrated the peripheral nerves (sciatic, brachial plexus) and intramuscular nerve branches. No evidence of cranial nerve, central nervous system, radicular, bone marrow, splenic, or lymph node involvement.Similar to the chronic polyneuropathic variant of human diffuse neurolymphomatosis; a condition most commonly caused by an axonopathy resulting from infiltration of peripheral nerves with non-Hodgkin’s lymphoma

Histopathologic, Immunohistochemical, and Cytologic Analysis of Feline Myeloma-Related Disorders: Further Evidence for Primary Extramedullary Development in the Cat Vet Path 2008 Mar: cats with well-differentiated tumors more commonly have extramedullary involvement than human myeloma patients with well-differentiated tumors

Multiple Cystic Intestinal Duplications in a Cat Vet Path 2008 Mar: 3 separate cystic structures in the muscular layer of jejunum. One cyst had a 3-layered wall consisting of a dysplastic mucosa, a regularly structured submucosa, and partly double-layered muscularis, contained neurons resembling a myenteric plexus. The remaining 2 cysts had similar structures except for granulation tissue lining the lumen. Duplication of GI is most commonly seen in Ileum and esophagus.

Photodamage in Feline Skin Vet Path 2008 May: Clinical and Histomorphometric Analysis:  A positive correlation was obtained between age, degree of edema and sclerosis in the upper dermis, telangiectases, squamatization of basal keratinocytes, and epidermis thickness and the degree of PD. The area occupied by adnexal structures in the dermis diminished with increased PD. Dermal sclerosis and edema  best  separated  the  3  groups.

Noncongophilic Fibrillary Glomerulonephritis in a Cat Vet Path 2008 May: nephrotic syndrome, mild increase in cholesterol, low total protein, severe hypoalbuminemia, and high proteinuria with a high protein-to-creatinine ratio. histologic examination : interstitial nephritis and  a  diffuse glomerulonephritis,  with  multifocal  thickening  of  the  Bowman’s  capsule. Transmission electron microscopy showed widespread fibrillary deposits in the glomerular basement membrane and in the mesangium. These fibrils ranged between 18 and 26 nm in diameter and were Congo red  negative,  which  allowed  their  differentiation  from  amyloid. Immunohistochemistry demonstrated  expression  for  immunoglobulin  M (IgM) and  immunoglobulin  G (IgG) within  the mesangium. Renal deposits of Congo red–negative amyloid-like fibrils have been described in humans, horses, monkeys, and dogs

Nasal Acinic Cell Carcinoma in a Cat Vet Path 2008 May: acinic cell carcinoma arising from a minor salivary gland of the nasal cavity. Acinic cell carcinoma is a rare tumor in veterinary medicine. The tumor is composed mainly of cells resembling serous cells of salivary glands and originates from major or minor salivary glands.

Pathology of Experimental SARS Coronavirus Infection in Cats and Ferrets.  Vet Pathol 45:551–562 (2008). All infected cats and ferrets had diffuse alveolar damage associated with SARS-CoV antigen expression.  SARS-CoV antigen expression occurred mainly in type I and II pneumocytes and serous cells of tracheo-bronchial submucosal glands of cats and in type II

pneumocytes of ferrets. ACE2 expression occurred mainly in type I and II pneumocytes, tracheo-bronchial goblet cells, serous epithelial cells of tracheo-bronchial submucosal glands in cats, and type II pneumocytes and serous epithelial cells of tracheo-bronchial submucosal glands in ferrets.  syncytia and hyaline membranes were not observed.

Feline Systemic Reactive Angioendotheliomatosis: Eight Cases and Literature Review. Vet Pathol 42:608–617 (2005).  Microscopic examination revealed occlusive, intraluminal proliferations of spindle cells within small vessels. The heart was consistently involved, and myocardial dysfunction was the probable cause of illness in all cats. Immunohistochemically, the majority of intravascular cells expressed von Willebrand factor, and a smaller number expressed smooth muscle actin, compatible with a dual population of endothelial cells and pericytes.  The histopathology resembles reactive angioendotheliomatosis in humans, a benign cutaneous intravascular endothelial and pericytic proliferative condition.

Neuropathology of Italian Cats in Feline Spongiform Encephalopathy Surveillance.  Vet Pathol 45:626–633 (2008). neoplasia (21.8%), toxic-metabolic encephalopathy (18.2%),granulomatous encephalitis (15.5%), suppurative encephalitis (4.6%), trauma (3.6%), circulatory disorders (3.6%), degeneration (2.7%), nonsuppurative encephalitis (2.7%), and neuromuscular diseases (1.8%). No histologic lesions were found in 20% of the brains, and samples from 5.5% of the cats were rejected as unsuitable.

Feline Pulmonary Langerhans Cell Histiocytosis with Multiorgan Involvement. Vet Pathol 45:816–824 (2008). Macroscopically, extensive, multifocal to confluent, pulmonary masses were evident. Infiltration of pancreas (2 cats), kidneys (1 cat), liver (1 cat), as well as tracheobronchial, hepatosplenic, or mesenteric lymph nodes (2 cats) was observed by gross or microscopic examination. The infiltrating cells had histiocytic morphology with cytologic atypia characterized by anisokaryosis and  hyperchromasia.  Lesional histiocytes expressedvimentin, CD18, and E-cadherin.   Transmission electron microscopy demonstrated intracytoplasmic organelles consistent with Birbeck’s granules of Langerhans cells in the lesional histiocytes.

Cutaneous Rhabdoid Tumor in a Cat.  Vet Pathol 45:897–900 (2008). Rhabdoid tumor is a highly aggressive neoplasm of unknown cellular origin in humans, usually occurring in thekidney and central nervous system of infants or children. A subcutaneous mass in a 13-year-old male  mixed-breed  cat  was  composed  of  nests  or  sheets  of round  to  polygonal  cells  with  glassy eosinophilic cytoplasmic inclusions. Immunohistochemically, many neoplastic cells expressed vimentin, localized to the cytoplasmic inclusions, whereas the cytoplasm of some neoplastic cells was diffusely positive  for neuron-specific  enolase,  neurofilament,  or  S-100  protein.  By  electron  microscopy,  the cytoplasmic  inclusions  were  found  to  be  composed  of  aggregates  of intermediate  filaments.

Prostatic Squamous Metaplasia in a Cat with Interstitial Cell Neoplasia in a Retained Testis.  Vet Pathol 45:905–909 (2008). During a celiotomy and prepubic urethrostomy, a retained testis, stenosed urethra, and irregularly enlarged prostate were observed. Histopathologic diagnosis was retained testis with a well-differentiated interstitial cell tumor, a poorly differentiated interstitial cell tumor,  and  marked  squamous  metaplasia  of  the  prostatic  epithelium  with  suppurative  prostatitis. Neoplastic  interstitial  cells  were  immunoreactive  for Melan  A, consistent  with  reports  of  Melan  A expression in steroid hormone-producing tissue.

Feline intestinal T-cell lymphoma: assessment of morphologic and kinetic features in 30 cases.  J Vet Diagn Invest 21:277–279 (2009). Neoplastic lesions were composed predominantly of small (n 5 21) or medium to large (n 5 9) anaplastic cells.

Metastatic angioinvasive lymphoma (lymphomatoid granulomatosis) in a cat. J Vet Diagn Invest 21:390–394 (2009). Angioinvasive  lymphoma  (AIL),  often  referred  to  as lymphomatoid granulomatosis, is a rare lymphoproliferative  disease  that  primarily  affects  the  lung.  Features  of AIL  include  a polymorphous  lymphoid  infiltrate, transmural invasion of blood vessel walls by atypical lymphoid cells, angiodestruction, and necrosis. A subcutaneous mass was characterized histopathologically by granulomatous inflammation, sheets of large atypical lymphoid cells, and necrosis. The walls of the small and medium caliber blood vessels were invaded transmurally by atypical lymphoid cells. A diagnosis of angioinvasive lymphoma (AIL), or lymphomatoid granulomatosis, was made based on histopathologic findings. neoplastic cell infiltrates were seen in adjacent skeletal  muscle,  right  superficial  inguinal  lymph  node,  liver,  and  spleen.  By  immunohistochemistry,  variable numbers  of  neoplastic  cells  expressed B-lymphocyte  antigen  36  (BLA36)  or  cluster  of  differentiation  (CD)3 markers, indicative of B- and T-cell lineages, respectively. Neoplastic cells were uniformly positive for vimentin and uniformly negative for cytokeratins and myeloid/histiocytic antigen.

Clinical, Histologic, and Immunohistochemical Analyses of Feline Squamous Cell Carcinoma In Situ: Two forms actinic keratosis (AK) and Bowenoid in situ carcinoma (BISC; Gross AK=plaque like to papillated, solitary, on pinnae, nose and eyelids of white cats. BISC=multifocal, crusted plaque, any location including dark pigmented areas; Histo: feline AK is less hyperplastic and hair follicles less deeply affected. Conclusion: BISC can be reliably diagnosed histologically. IHC for p53 and papillomavirus antigen support that sun exposure and papillomavirus are involved in pathogenesis of AK and BISC respectively

Feline Gastrointestinal Eosinophilic Sclerosing Fibroplasia: vomiting was main presenting sign; peripheral hypereosinophilia in 58% cases; 50% had mass in pyloric sphincter; lymph nodes were also involved (both sclerosing and eosinophilic lympadenitis) Histo: branching and anastomosing trabeculae of dense collagen, with large spindle cells (myofibrolasts), infiltrate of eosinophils, mast cells and neutrophils; did not extend to serosa;

Immunophenotypic and Histologic Classification of 50 Cases of Feline Gastrointestinal Lymphoma: Vet Pathol 46:259-268 (2009). Overall, B-cell tumors predominated at 54%, T-cell tumors comprised 38. Of all the GI lymphoma, small intestinal lymphoma predominated, with 74% (37/50) of cats affected: T-cell tumors comprised 52% and 38% was B-cell tumors. Allgastric lymphomas were of B-cell lineage (diffuse large B-cell lymphoma of immunoblastic nuclear type)

Molecular Characterization of Feline COX-2 and Expression in Feline Mammary Carcinomas: COX-2–derived prostaglandins are thought to promote cancer progression by angiogenesis, apoptosis resistance, the immune system, and tumor cell invasiveness. Upregulated expression of COX-2 has been documented in many cancers in humans. Feline COX-2 amino acid sequence is highly similar to other mammalian COX-2 homologs. 87% of mammary carcinoma expressed COX-2 at a low, intermediate and levels

The Progenitor Cell Compartment in the Feline Liver: An (Immuno)Histochemical Investigation.  Vet Pathol 46:614–621 (2009). In acute and chronic feline liver diseases a ductular reaction is present, whether in the parenchyma or in a portal or septal location. The putative progenitor cells could easily be demonstrated by staining for CK7, whereas they were generally negative for Hepar1 and MRP2. In a parenchymal ductular reaction mitotic figures and cells with an intermediate hepatobiliary phenotype could be demonstrated. This is the first account of hepatic progenitor cells in feline liver.

Anal Sac Gland Carcinoma in 64 Cats in the United Kingdom (1995–2007).  Vet Pathol 46:677–683 (2009). Immunohistochemistry and the use of the glandular cytokeratin antibody (CAM 5.2).  Median survival of 3 months. Survival rates at 1 and 2 years were 19 and 0%, respectively.

Purkinje Fiber Dysplasia (Histiocytoid Cardiomyopathy) with Ventricular Noncompaction in a Savannah Kitten.  Vet Pathol 46:693–697 (2009). Abnormal  Purkinje  fibers  and  biventricular myocardial  trabeculation  or  noncompaction.  The  Purkinje  fibers  were  large,  angular,  and  tightly packed. They contained few disorganized myofibrils among a rarified cytoplasm. The fibers were distinct from adjacent myocytes and were immunohistochemically positive fordesmin, muscle actin, myoglobin, sarcomeric actin, and chromogranin A. These findings are identical to those that occur in children with histiocytoid  cardiomyopathy,  a  fatal  genetic mitochondrial  disorder  of  Purkinje  fibers.  Ventricular noncompaction   likely   has   a   multifactoral   cause   that   results   from   fetal   arrest   of   ventricular organizational  development  that  might  occur  in  conjunction  with,  or  independent  of,  histiocytoid cardiomyopathy.

Genetic variability of archived Cytauxzoon felis histologic specimens from domestic cats in Georgia, 1995–2007. J Vet Diagn Invest 21:493–498 (2009). Eleven different combined ITS1 and ITS2 sequences were identified, the majority of which were identical to those previously reported in fatally infected cats from Georgia. The findings of the current study document the existence of genetically distinct C. felis populations in historical samples and, together with data from contemporary samples, demonstrate a diverse population structure for C. felis.

Multiple endocrine neoplasia type-I-like syndrome in 2 cats. pp345-52. May 2006 AR

· 2 DSH cats: symmetric alopecia, insulin resistant DM, pit-dep. hyperadrenocorticism

· Skin: Atrophic dermatosis assoc w/hyperadrenocorticism; 1 also had paraneoplastic alopecia assoc w/pancreatic adenocarcinoma

· Both cats: Multiple invasive pancreatic β-cell carcinomas, pituitary corticotroph adenomas, thyroid C-cell & parathyroid chief cell hyperplasia; Pancreatic exocrine adenocarcinoma

Multiple endocrine neoplasia (MEN):

· MEN-1: Various combos of parathyroid, pituitary, and pancreatic endocrine tumors

o Also assoc with carcinoids, thyroid neoplasms, C-cell hyperplasia, adrenocortical hyperplasia/adenoma, mesenchymal tumors

o Autosomal dominant with mutation of menin gene

· MEN-2A: Thyroid medullary carcinoma, pheochromocytoma & parathyroid hyperplasia

· MEN-2B: Familial thyroid adenocarcinoma syndrome

· MEN-like syndromes in dogs, horses, bulls, ferrets, mice

Gastric Adenocarcinoma and Chronic Gastritis in Two Related Persian Cats. Vet Pathol 43:358-362 (2006 May)

– Intralesional adult Ollulanus tricuspis nematodes and rare surface-associated spiral-shaped bacteria were identified in one cat.

– No reports of gastric adenocarcinoma associated with O. tricuspis infection in the cat.

Other helminths: Spirocerca lupi, Schistosoma sp., and Taenia taeniaeformis larvae, are associated

Helicobacter spp. associated with gastric adenocarcinoma in humans, ferrets

Noninfectious chronic inflammatory lesions affecting the cat have a propensity for malignant transformation: vaccine-associated sarcoma and trauma-induced uveal sarcoma

Multicentric physeal dysplasia in 2 cats. pp388-90.  May 2006  NW

2 cats with feline physeal dysplasia and slipped capital femoral epiphysis

The retention of an open physis and the disorganization of the chondrocytes is a widespread, multicentric lesion (proximal and distal femurs and humerus) that precedes atraumatic separation

Physeal dysplasia in cats is a widespread multicentric disorder of chondrocytes that precedes the development of slipped capital femoral epiphysis.

A condition of young, predominantly male, frequently overweight cats

Helicobacter spp. in Cats: Association between Infecting Species and Epithelial Proliferation within the Gastric Lamina Propria J. Comp. Path. 2009, Vol. 141, 127e134 Histopathology: Lamina propria contained mild mononuclear inflammatory infiltration, the presence of lymphoid follicles, fibrosis and glandular degeneration. These changes were most severe in the pyloric antrum. There was significant association between infection with gastric Helicobacter spp. and the presence of lymphoid follicles, and between infection and epithelial proliferation in the antrum.

Occurrence, Morphological Characterization and Antigen Localization of Felid Herpesvirus-Induced Pneumonia in Cats: a Retrospective Study (2000e2006). Histopathology: The microscopic changes included fibrinonecrotic pneumonia and severe necrosis of the bronchial and bronchiolar epithelium.

Considered as a differential diagnosis for fibrinous bronchopneumonia in cats and IHC for confirmation (virus in the lungs).

Uncommon mediastinal cyst-like manifestation of feline infectious peritonitis Veterinary Record (2009) 165, 239-241 Gross lesions: Thickening of the parietal and visceral pleura and a cyst-like encapsulated effusion originating from the mediastinal pleura and taking up a large part of the left thorax, compressing the mediastinum and the heart over to the right side of the thorax. Histopathology: The encapsulated lesion originated from mediastinal pleura and had severe, diffuse, pyogranulomatous inflammation of the pleurae and pericardium. The pleura was positive for FVCoV by IHC.

Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 Expression in Canine and Feline Meningioma.  Vet Pathol 46:836–845 (2009). The most common histotype was malignant in dogs (12/28) and transitional in cats.  MMPs showed a diffuse cytoplasmic pattern. highest values of MMP-2 and MMP-9 were observed in a psammomatous and meningothelial tumor. It has been reported that a high proliferative index in the tumor is associated with low   progesterone   receptor   (PR) concentration, suggesting that PR expression in canine and feline meningiomas is a reliable prognostic factor in the evaluation of this tumor, as well as in humans respectively.

Reduced PTEN Protein Expression and Its Prognostic Implications in Canine and Feline Mammary Tumors.  Vet Pathol 46:860–868 (2009). Phosphatase  and  tensin  homolog  (PTEN)  belongs  to  the  group  of gatekeeper  tumor suppressor genes.  Significant loss of PTEN protein expression found in simple carcinoma histotype, lymphatic vessel invasion, lymph node metastases, distant organ  metastases,  tumor  dedifferentiation,  tumor  recurrence,  and  shorter  overall  survival.  In  feline mammary tumors, a significant correlation between loss of PTEN protein expression and lymphatic vessel invasion was found. Loss of PTEN expression could be a useful prognostic marker in canine mammary carcinomas.

Severe polymyositis and neuritis in a cat: JAVMA: Mononuclear cell inflammation with myofibers loss, atrophy, and fibrosis.  In nerves and muscle. Negative for toxoplasma. Formalin fixation reduces enzyme activity and glycogen and lipids. Impossible to identify muscle fiber types.

A Retrospective Study of Eyelid Tumors from 43 Cats. Vet Pathol 46:916–927 (2009). squamous   cell   carcinomas (SCCs) >   mast   cell   tumors   (MCTs) >  6 hemangiosarcomas (HSAs) > 4 adenocarcinomas (ACAs) > 3 peripheral nerve sheath tumors (PNSTs) > 3 lymphomas =  apocrine hidrocystomas (AHCs) > hemangiomas.  HAS, MCT, SCC had excisional cure and good prognosis.

Overexpression of HER-2 in Feline Invasive Mammary Carcinomas: An Immunohistochemical Survey and Evaluation of Its Prognostic Potential: Her-2/neu (c-erbB-2) is a transmembrane receptor with intrinsic tyrosine-kinase activity, and it is related to the epidermal growth receptor family, believed to play important roles in cancer development. The overexpression of this protein is caused by the amplification of the HER-2/neu protooncogeHER-2. overexpression was detected in 59 % of  carcinomas. Overexpression was significantly correlated with the shorter overall survival. However, the HER-2 overexpression did not show significant correlation with histologic type, tumor grading, or presence of lymphatic invasion.

Melanotroph Pituitary Adenoma in a Cat with Diabetes Mellitus: cat was referred for insulin-resistant diabetes mellitus and had a ravenous appetite and a dull coat. Pituitary adenoma originating from the pars intermedia with infiltration into the neural lobe. The adenoma immunostained intensely positive for  –MSH and only weakly for ACTH. ACTH-independent cortisol production was probably due to the (weak) glucocorticorticotropic effects of the extremely high plasma concentration of  -MSH. Cats presenting with insulin-resistant diabetes mellitus DDX= GH excess (acromegaly), hyperadrenocorticism, double adenoma (somatotroph and corticotroph adenoma leading to GH excess and hypercortisolism), melanotroph adenoma.

Copper-associated Chronic Hepatitis and Cirrhosis in a European Shorthair Cat: cat had ascites and an irregularly nodular liver. Histo: chronic hepatitis with cirrhosis associated with massive accumulation of copper in hepatocytes and macrophages, particularly in the fibrotic areas between the regenerative nodules.

Morphologic Features and Development of Granulomatous Vasculitis in Feline Infectious Peritonitis: FIP seems to develop in the individual infected animal when FCoV acquires virulence by deletions in open reading frames 3 and 7, coding for nonstructural proteins of unknown function. Vascular inflammatory processes were restricted to small and medium-sized veins mainly in leptomeninges, renal cortex, eyes, lungs, liver and mainly composed of macrophages. Lack of arterial involvement and the involvement of small and medium-sized veins rather than postcapillary venules excludes the classification of FIP vasculitis as small or medium-sized vessel vasculitis. Neither in this nor in an experimental study was there evidence for direct infection of EC by FCoV.

Hepatobiliary Neuroendocrine Carcinoma in Cats: A Clinicopathologic, Immunohistochemical, and Ultrastructural Study of 17 Cases: The hepaticneuroendocrine carcinomas had two patterns, one with acinar structures separated by vascular stroma lined by cuboidal/columnar cells and the other solid with groups of anaplastic cells. The extrahepatic neuroendocrine carcinomas and the gallbladder neuroendocrine carcinoma were chr by solid sheets of round to oval cells with fibrovascular stroma. IHC: 100%  stained with NSE; one bile duct carcinoma and the gallbladder carcinoma stained with chromogranin; four of five bile duct carcinomas and the gall bladder carcinoma stained with synaptophysin; and one bile duct carcinoma stained with gastrin

Lipid-rich Carcinoma of the Mammary Gland in a Cat: multilobular, expansile mass in which lobules were composed of tubuloacinar structures formed by atypical round to polygonal cells, which contained foamy to microvacuolated cytoplasm. Neoplastic cells were positive for cytokeratin and and the vacuoles stainedpositively with Oil RedO and negatively with PAS and Alcian blue stains.

Pathology of End-stage Remodeling in a Family of Cats with Hypertrophic Cardiomyopathy: HCM is heterogeneous disease with many phenotypes, including the dilated phase or end stage, which we propose to call end-stage hypertrophic cardiomyopathy (ES-HCM). Grossly, there was left atrial dilation with relative thinning of the interventricular septum (IVS) and left ventricular free wall (LVFW) and dilation of the ventricular chamber. The left atrium contained large thrombi in 2 of 3 cats, and all three cats died following thromboembolization of the aortic bifurcation. Histo: all 3 cats had subendocardial and myocardial fibrosis, predominantly of the IVS and LVFW, and 1 cat had acute, myocardial infarcts with mononuclear cell infiltrates. The pathogenesis of ES-HCM is uncertain, but theories implicate occlusion of the coronary blood flow by thickening of the coronary vessels, coronary vascular thromboembolism or coronary vessel spasm, apoptosis of myocytes, and myocardial hypertrophy beyond the ability of the vasculature to supply blood.

Idiopathic Complex Polysaccharide Storage Disease in an Abyssinian Cat: A glycogen storage disease affecting primarily the skeletal muscle and, to a lesser degree, the cardiac muscle, spinal cord, and brain was diagnosed in a 10-year-old neutered Abyssinian cat with a 4-year history of paresis progressing to acute paralysis. Histo: tissues contained inclusions that were pale basophilic in hematoxylin and eosin–stained slides, diastase resistant, periodic acid–Schiff positive, and blue-to-almost black with iodine stain. Glycogen storage disease affecting multiple tissues has been reported only in Norwegian forest cats as a lethal inherited metabolic disease due to a deficiency of glycogen branching enzyme (glycogen storage disease type IV).

Feline Systemic Reactive Angioendotheliomatosis: Eight Cases and Literature Review: rare, multisystemic intravascular proliferative disorder was identified in 8 cats. Histo: occlusive, intraluminal proliferations of spindle cells within small vessels. The heart was consistently involved, and myocardial dysfunction was the probable cause of illness in all cats. Other organs commonly involved were spleen, kidney and LN. Intravascular cells expressed vWF factor, and a smaller number expressed smooth muscle actin, compatible with a dual population of endothelial cells and pericytes, suggesting a reactive rather than a neoplastic process.

Two Cases of Feline Malignant Craniopharyngioma: Tumors at the cranial base in 2 cats were diagnosed as malignant craniopharyngioma. Histo: the tumor was divided into four parts: 1) a small acinus part, in which relatively large cells with a pale cytoplasm composed small acini; 2) a duct part, in which small cuboidal cells composed ducts; 3) a cyst part, in which there were large cysts lined with flat cells; and 4) a pavement part, in which large multiangular-shaped cells proliferated in a pavement pattern. Some of the epithelial cells were keratin positive.Craniopharyngioma is a generally benign tumor that develops over the diaphragm of sella or sometimes in the sella turcica, and consists of neoplastic cells with characteristics of epithelium.

Putative Metronidazole Neurotoxicosis in a Cat: The cat had been treated for inflammatory bowel disease with prednisone and metronidazole. Cl. signs acute tetraparesis,unresponsiveness, tremors, and vocalization. Necropsy revealed no significant macroscopic lesions. Histologic evaluation revealed multifocal, fairly well-demarcated foci of necrosis in the brainstem, extending from the diencephalon to the medulla oblongata.

Histologic Features Associated with Tritrichomonas foetus-induced Colitis in Domestic Cats: T. foetus is a venereal pathogen of naturally bred cattle. In domestic cats, T. foetuscolonizes the colon, resulting in chronic, large-bowel diarrhea. More common in young, densely housed cats, and there is no effective treatment. The presence of colonic trichomonads was the most diagnostic histologic feature. Organisms were identified in all cats, but in only 56% sections of colon. Trichomonads were generally present in close proximity to the mucosal surface and less frequently in the lumen of colonic crypts. The presence of colonic trichomonads was consistently associated with mild-to-moderate lymphoplasmacytic and neutrophilic colitis, crypt epithelial cell hypertrophy, hyperplasia and increased mitotic activity, loss of goblet cells, crypt microabscesses, and attenuation of the superficial colonic mucosa. In two of the cats, histologic lesions were more severe and were associated with invasion of trichomonads into the lamina propria and/or deeper layers of the colon.

Aberrant p53 Expression in Feline Vaccine-associated Sarcomas and Correlation with Prognosis: Eighty spontaneously occurring feline vaccine-associated sarcomas (VAS) were evaluated. Cytoplasmic staining for p53 was a consistent pattern of VAS, occurring in 44% of tumors evaluated. Cats with tumors that exhibited cytoplasmic p53 had significantly shorter time to tumor recurrence compared to those cats with tumors that exhibited nuclear p53 staining but no significant difference in survival outcome was observed. Most mutations of p53 occur within several “hot spot” locations of the genome, particularly exons 5–8, which are clearly linked to tumorogenesis. Mutations in p53 have been identified in surroundinghistologically normal tissues up to 5 cm distant from the tumor known as field cancerization (preneoplastic condition).

Feline large granular lymphocyte (LGL) lymphoma with secondary leukemia: primary intestinal origin with

predominance of a CD3/CD8αα phenotype. pp15-28. Jan 2006  NW

Main point: An intestinal intraepithelial lymphocyte (IEL), CD3e+/CD8aa cytotoxic T cell: origin for feline large granular lymphocyte (LGL) – Sites of neoplastic cell infiltrates: o Small intestine (jejunum>ileum>duodenum)  – some are epitheliotropico Mesenteric LN, liver, spleen, kidneys, and/or bone marrow

phenotype (most common)

Giant cell osteosarcoma (OSA) in the calvarium of a cat. pp179-82. March 2006  MT Multinucleate giant cells (MGCs) VIM +, TRAP+, CD68, CD51 ; neg for S-100, CK (suggests ocl origin); MGCs also MHC-II neg (suggests obl origin)

Hormone receptor expression in female malignant mammary tumors.  JAVMA. More ER and PR à Benign tumors; Malignant tumors with ER and PR expression had higher survival times. Only PR expression was associated with significant survival time.

Expression of KIT Receptor in Feline Cutaneous Mast Cell Tumors. Vet Pathol 46:878–883 (2009). According to the results, there was no correlation between the type of MCTs and KIT expression, although the use of feline KIT immunohistochemistry could be useful to assess the mast cell origin. Well-differentiated MCTs, Atypical MCTs, pleomorphic MCT showed diffuse cytoplasmic KIT stain.

Hypertensive Encephalopathy in Cats with Reduced Renal Function: cats developed a progressive syndrome of lethargy, ataxia, blindness, stupor, and seizures following an abrupt increase in blood pressure associated with a surgical reduction in renal mass. The cats had severe gross brain edema, evidenced bycerebellar coning and cranial displacement over the corpora quadrigemina and cerebral widening and flattening of the gyri. Histo; interstitial edema was most pronounced in the cerebral white matter. Hypertensive vascular lesions were present as hyaline arteriolosclerosis in one cat and hyperplastic arteriolosclerosis in the other. Rare foci of parenchymal microhemorrhages and necrosis were also observed Hypertensive encephalopathy is an acute neurologic syndrome precipitated by an abrupt, sustained rise in systemic arterial blood pressure and is an important cause of neurologic disease in cats with chronic kidney disease.

Immunohistochemical Expression of c-KIT Protein in Feline Soft Tissue Fibrosarcomas. Vet Pathol 46:934–939 (2009). KIT immunoreactivity in feline ST FSA does not correlate with the histologic grade (P 5 .141, X 2 5 2.166), survivability (P 5 .241, X 2  5 1.373), or whether the neoplasm was a spontaneous or an injection site FSA (P 5 .074, X 2  5 3.184).

Extraintestinal pathogenic Escherichia coli–induced pneumonia in three kittens and fecal prevalence in a clinically healthy cohort population. J Vet Diagn Invest 21:609–615 (2009). hemorrhagic or bloody fibrinoserous thoracic fluid.  acute necrotizing and hemorrhagic pneumonia and pleuritis, with numerous intralesional small Gram-negative rods. A pure culture of a distinct serotype of Escherichia coli was identified in lung tissue from each kitten (O4:H5, O6:H7, O6:H5). ExPEC-associated genes include cytotoxic necrotizing factors (cnf-1, cnf-2), P fimbriae adhesins ( papG allele I and papG allele III), major structural subunit of the P  fimbrial   shaft  ( papA),  pilus   assembly  protein ( papC ), S fimbriae (sfa), F1C fimbriae ( foc), type 1 fimbriae  ( fim),  hemolysin  D  (hlyD),  pathogenicity-associated island marker (malX-‘‘PAI’’), novel catecholate  siderophore  receptor  (iroN ),  Yersinia  siderophore   receptor  ( fyuA),  genes  associated  with capsular  polysaccharide  synthesis  (kpsMTII ),  and outer membrane peptidase (ompT ).11–13,16,18 The roles that ExPEC virulence attributes play in the pathogenicity  of  ExPEC  strains  were  previously  summarized.1,11–13,18   In  brief,  pili  or  fimbriae  and  fimbrial adhesin molecules promote adherence and colonization in tissue, Cnf-1 and HlyD are cytotoxins that evoke tissue necrosis, and siderophore receptors are important for  iron  acquisition.  ExPEC  isolates  were  associated with  urinary  tract  infections,  pneumonia,  septicemia, and meningitis  in humans,17  urinary  tract  infections, genital  infections,  and  septicemia  in  companion  and food animals,  and necrohemorrhagic pneumonia in dogs, in a horse, and in a group of shelter cats.  hemolytic E. coli fecal isolates from the cohort population, each of which had a genetic profile consistent with that typical of ExPEC.

Quadrigeminal arachnoid cysts in a kitten and a dog. J Vet Diagn Invest 21:707–710 (2009). Kitten- Congenital- mild internal hydrocephalus, caudal cerebellar coning, and cerebellar herniation through the foramen magnum were associated with a congenital quadrigeminal arachnoid cyst compressing the  rostral  cerebellum  and  shifting  the  entire  cerebellum  caudally Dog- In  contrast,  a  possibly  acquired quadrigeminal  cyst  was  observed  in  a  2-year-old  male  neutered  Yorkshire  Terrier  in  association  with necrotizing encephalitis.

Disseminated cutaneous mast cell tumors with epitheliotropism and systemic mastocytosis in a domestic cat. J Vet Diagn Invest 21:710–715 (2009). Multifocally, the neoplastic cells formed multiple small clusters of 3–5 cells within the epidermis. Distinct cytoplasmic granules were evident within the neoplastic cells with toluidine blue and Giemsa stains. The neoplastic cells were immunoreactive for c-KIT and lacked immunoreactivity for cluster of differentiation 3 with immunohistochemistry.  A complete necropsy revealed sheets of similar neoplastic mast cells within the spleen, liver, and individual cells scattered within the bone marrow.

Feline Peripheral Nerve Sheath Tumors: Histologic, Immunohistochemical, and Clinicopathologic Correlation (59 Tumors in 53 Cats) . Vet Pathol 46:1166–1180 (2009). All  of  the  tumors  involved  skin,  subcutis,  skeletal  muscle,  and/or  mucous  membranes. Histologically,  the  tumors  were  composed  of  compact  to  loosely  arranged  streams  and  fascicles  of spindled  cells  with  eosinophilic,  often  wavy  cytoplasmic  processes;  small  to  occasionally  moderate amounts of collagenous to myxoid matrix; and nuclear palisading. Immunohistochemically, all tumors were positive for vimentin and S-100 protein, 44 of 59 were positive for glial fibrillary acidic protein (GFAP), and all were negative for muscle specific actin.   34 benign tumors with Antoni A areas that were S-100 protein and GFAP positive, 9 benign tumors that lacked Antoni A areas and were S-100 protein positive and GFAP negative, and 16 tumors with features of malignancy.

An In Situ Hybridization and Immunohistochemical Study of Cytauxzoonosis in Domestic Cats. Vet Pathol 46:1197–1204 (2009). Immunohistochemistry with an antilysozyme antibody  confirmed  the  macrophage  origin  of  the  infected  cells.  Using  an  antibody  specific  for calprotectin (Mac387), parasitized cells were markedly devoid of this protein, which may explain the lack of diapedesis and vascular crowding of parasitized cells.  Immunohistochemical  labeling  for  2  proliferation  markers,  proliferating  cell  nuclear  antigen (PCNA) and p53, indicated that parasitized cells have a heightened replicative ability, which is probably an additional parasite-driven modification to facilitate survival and transmission.

The Experimental Induction of Leukoencephalomyelopathy in Cats. Vet Pathol 46:1258–1269 (2009). Leukoencephalomyelopathy of undetermined etiology has been described in specific pathogen-free cats. A study was established to assess if the long-term feeding of a gamma-irradiated diet could induce this disease. The elevated total antioxidant status of spinal cord segments and hepatic superoxide dismutase concentration of cats fed typical and high-end treated diets suggested free-radical involvement in the pathogenesis. The significantly elevated peroxide concentrations of the irradiated diets (1,040% and 6,440% of untreated values) may have resulted in increased oxidative insult, a factor possibly exacerbated by the treated diets’ reduced vitamin A content. This study has reproduced leukoencephalomyelopathy in cats similar to spontaneous outbreaks by feeding a gamma-irradiated dry diet with elevated peroxide and reduced vitamin A concentrations.

Peliosis Hepatis in Cats Is Not Associated With Bartonella henselae Infections. Veterinary Pathology 47(1) 163-166. In humans and dogs, Bartonella henselae has been linked to peliosis hepatis.  The authors failed to detect B. henselae nucleic acid or antigen in any of the affected liver specimens. These findings suggest that, unlike in humans and dogs, peliosis hepatis in cats may not be significantly associated with a B. henselae infection.

The same papillomavirus is present in feline sarcoids from North America and New Zealand but not in any non-sarcoid feline samples. J Vet Diagn Invest all members of the genus Deltapapillomavirus. 22:97–100 (2010). Feline sarcoid–associated PV appears most similar to BPV-1, OvPV-1, and BPV-2, which are all members of the genus  Deltapapillomavirus. Cows are not the reservoir.

Concurrent nasal adenocarcinoma and rhinosporidiosis in a cat. J Vet Diagn Invest 22:155–157 (2010). Pink fleshy polyps protruding from each nostril- the polyps were composed of hyperplastic nasal epithelium and submucosal stroma that contained sporangia consistent with Rhinosporidium seeberi. The nasal cavity had extensive bone and cartilage loss and contained a tan firm mass in the caudal region of the nasal cavity near the cribriform plate. On histologic examination, the mass was a nasal Adenocarcinoma.

Pathological Findings Associated with Experimental Infection by Trypanosoma evansi in Cats.  J. Comp. Path. 2010, Vol. 142, 170e176. Gross findings – generalized muscle atrophy, anemia, icterus, lymphadenopathy and Splenomegaly, less frequently corneal opacity, subcutaneous oedema (mainly of the head) and hydropericardium. Trypomastigotes of T. evansi were observed in impression smears prepared from the aqueous humor. Microscopically, there was lymphoid hyper-

plasia of the spleen and lymph nodes. The animals with corneal opacity had mild corneal oedema and accumulation of fibrin and inflammatory cells (neutrophils and plasma cells) in the anterior chamber. Similar inflammatory cells infiltrated the iris, ciliary body, corneoscleral limbus and conjunctiva.

FeLV A and B -Vp 36:91 1999

Recombinant feline leukemia virus (FeLV) variants establish a limited infection with altered cell tropism in specific-pathogen-free cats in the absence of FeLV subgroup A helper virus

Feline leukemia virus subgroup B (FeLV-B) is commonly associated with feline lymphosarcoma and arises through recombination between endogenous retroviral elements inherited in the cat genome and corresponding regions of the envelope (env) gene from FeLV subgroup A (FeLV-A)

In vivo infectivity for FeLV-B is thought to be inefficient in the absence of FeLV-A. Proposed FeLV-A helper functions include enhanced replication efficiency, immune evasion, and replication rescue for defective FeLV-B virions.

Thyroid follicular adenoma/hyperplasia- VP 36:117

Overexpression of c-Ras in hyperplasia and adenomas of the feline thyroid gland: an immunohistochemical analysis of 34 cases

all cases of nodular follicular hyperplasia/adenomas stained positively for overexpression of c-Ras protein . The most intensely positively staining regions were in luminal cells surrounding abortive follicles. There was no detectable staining for either Bc12 or p53 in any of the cats. These results indicated that overexpression of c-ras was highly associated with areas of nodular follicular hyperplasia/adenomas.

Pleomorphic cutaneous mast cell tumors in cats- VP 39:452

Histopathology and Biologic Behavior of Pleomorphic Cutaneous Mast Cell Tumors in Fifteen Cats Most feline cutaneous mast cell tumors (CMCT) are behaviorally benign; however, there is a subset of these tumors with marked pleomorphism (previously termed poorly differentiated) that have been reported to be more aggressive. In this study, the large majority of feline pleomorphic CMCT were behaviorally benign. Mitotic rate is likely an important prognostic indicator of CMCT behavior.

Malignant melanoma in cats- VP34:31 1997

Cutaneous malignant melanomas in 57 cats: identification of (amelanotic) signet-ring and balloon cell types and verification of their origin by immunohistochemistry, electron microscopy, and in situ hybridization

Out of the malignant melanomas all epithelioid, spindle, and mixed epithelioid/spindle cell types showed pigmentation, signet-ring and balloon cell types were often amelanotic. Immunohistochemical examination of the melanomas revealed a positive staining for S-100, vimentin, and neuron-specific enolase. The melanomas were negative for muscle cell markers, except in some of the signet-ring cell melanomas; 13 of 21 tumors showed a weak positive staining for polyclonal desmin. Electron microscopic examination of signet-ring cell melanomas revealed an abundance of intermediate filaments, whereas in some of these tumors a few cells with melanosomes were found. Nonisotopic in situ hybridization for mRNA encoding for tyrosinase verified the melanocytic origin of the amelanotic signet-ring and balloon cell melanomas.

FeLV enteritis- VP37:129 2000

In FeLV-associated enteritis, FeLV gp70 and p15E were strongly expressed in intestinal crypt epithelial cells. In contrast, FeLV-positive cats without intestinal alterations showed only faint staining for gp70 and p15E and comparatively strong p27 expression in these cells. Findings suggest a direct relation between FeLV infection and alterations in intestinal crypt epithelial cells that may be attributed to the envelope proteins gp70 andp15E and/or their precursor protein.

Fluoroquinilone antibiotics in cats – JAVMA 221(11): 1568, 2002

Histologic examination of 2 eyes revealed diffuse loss of the outer nuclear and photoreceptor layers and hypertrophy and proliferation of the retinal pigment

epithelium. It was concluded that enrofloxacininduced retinal degeneration might be a rare and idiosyncratic reaction in some cats.5

FeLV associated myelopathy- VP 39:536-545 2002

Microscopically, white-matter degeneration with dilation of myelin sheaths and swollen axons was identified in the spinal cord and brain stem of affected animals. Neither neoplastic nor hematologic diseases commonly associated with FeLV infection were present. Fungal and protozoal infection in one animal was suggestive of impaired immune competence. Immunohistochemical staining of affected tissues revealed consistent expression of FeLV p27 antigens in neurons, endothelial cells, and glial cells. Furthermore, proviral DNA was amplified from multiple sections of spinal cord as well as intestine, spleen, and lymph nodes.

Feline pulmonary langerhans cell histiocytosis- features (Birbecks granules?) and tissues-VP 45:816

Lesional histiocytes expressed vimentin, CD18, and E-cadherin. Expression of E-cadherin was usually markedly reduced in extra-pulmonary lesions, which is consistent with possible down-regulation of E-cadherin associated with distant migration from the lung. Transmission electron microscopy demonstrated intracytoplasmic organelles consistent with Birbeck’s granules of Langerhans cells in the lesional histiocytes in all cats

Feline Progressive HIstiocyttosis- 43:646

Solitary or multiple nonpruritic firm papules, nodules, and plaques had a predilection for feet, legs, and face. Lesions consisted of poorly circumscribed epitheliotropic (13/30) and nonepitheliotropic (17/30) histiocytic infiltrates of the superficial and deep dermis, with variable extension into the subcutis. The histiocytic population was relatively monomorphous early in the clinical course. With disease progression, cellular pleomorphism was more frequently encountered. Histiocytes expressed CD1a, CD1c, CD18, and major histocompatibility complex class II molecules.

Feline HCM- McGavin p218 3rd ed

MIddle aged males (1-3 years)- CHF, 10-20% posterior paresis from thromboembolism

Persians, American Shorthairs, And Maine Coones.

Hypertrophy of left ventricle and IVS, LEft atrial dilation. Myocardial disarray and disorganization with interweaving, myocyte hypertrophy, interstitial fibrosis.

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