Luteinizing follicular cyst in a dog

History: Tissue from an 11 month old female Great Dane.  The tissue was removed during a routine spay surgery and submitted for histopath due to abnormal appearance.

Ovary: Large corpus luteum at the top of the image and a smaller luteinizing follicle in the center

Ovary: Higher magnification of the luteinizing cells lining the cyst

Ovary:  In each section examined there are primary follicles present in a fibrovascular stroma.  There are two normal corpora lutea present consisting of a large solid mass ofpolygonal cells with large intracytoplasmic lipid vacuoles (luteinized cells). In addition there are two large cystic follicles partially lined by luteinized cells and partially lined by follicular epithelium.

Comment:

Luteinized ovarian cysts are derived from anovulatory Graffian follicles. They are differentiated from cystic corpora lutea by the absence of a break in the wall of the cyst where ovulation has occurred.  They are uncommon in dogs and the clinical significance is usually negligible. They can occur in clinically normal dogs, and be seen in dogs with pyometra and cystic endometrial hyperplasia. CEH and pyometra often occurs in the absence of such cysts, and generally happens through persistent hormonal stimulation of the corpora lutea which can persist following ovulation.

Bacterial infection or foreign material within the uterus may cause CEH and pyometra during the luteal phase of the cycle. Excess estrogenic stimulation can also lead to CEH-pyometra. Progesterone  is the major hornome stimulating CEH and pyometra in the dog; but the endometrium responds best to progesterone following priming by estrogen.

Tissue from an 11 month old female Great Dane was submitted for histopathology.  During the spay

surgery the submitting veterinarian noticed an abnormal anatomical arrangement of the reproductive

tract and requests identification of the submitted tissue to see if it is ovarian or lymphoid.

Whats Your Diagnosis #3

History: A feeder pig was found dead in the morning, it was thinner than its penmates.

Gross Necropsy: (no photos)

The lungs were loosely adhered to the thoracic body wall by multiple strands of fibrin. The lungs were diffusely edematous and firm.

The pericardium contained approximately 200 mls of fluid. The right ventricle was severely enlarged and the pulmonary trunk was dilated.

There was diffuse serous atrophy of fat.

Histopathology:

Lung:

Differential Diagnoses for interstitial pneumonia and vasculitis in a pig:

1. PRRS virus

2. Porcine Circovirus-2-

3. Classical Swine Fever (Pestivirus)

To Be Continued….

What other tissues would you examine?   What histologic lesions do you expect to find with each of the differentials above?

To see our diagnosis and discussion click here

Uterine Adenocarcinoma in a Rabbit

History: An 11 year old intact female rabbit  had a chronic history of Pasteurella multocida snuffles and head tilt which had resolved.   Her owner noticed she started to have increased abdominal component of respiration which progressed to open mouth breathing.  A mass was palpated in the caudal abdomen during examination.

Gross Necropsy:

The lungs were almost completely replaced by large numbers of individual to coalescing firm white nodules ranging in size from 0.5 cm to 3 cm in diameter and projecting 1-2 cm from the lung surface. On cut surface the nodules were firm and homogeneously white.

Lungs. liver, in situ: Multifocal tan firm nodules replace most of the lung tissue

Lungs, liver, closer view

Lungs (with pluck) removed

A 3.5 cm x 2 cm x 1 cm elliptical mass was present in the wall of the right uterine horn located approximately 1 cm from the ovary. The mass was irregular and composed of firm white nodules and softer grey areas.

Uterus and uterine horns: One horn is enlarged with a transmural mass

Uterine horn: Closer view of mass

Uterine horn: Lumen opened showing thickened uterine wall

The liver had multifocal firm white nodules (1.5 cm to 0.5 cm in diameter) scattered throughout the parenchyma.

An 11 year 9 month old intact female rabbit was presented for necropsy on 9/19/08. This doe had a

chronic history of Pasteurella multocida snuffles and head tilt which had resolved. On 9/18/08 her

owner noticed she started to have increased abdominal component of respiration which progressed to

open mouth breathing on 9/19/08. She had no previous indication of respiratory distress. A mass

palpated in the caudal abdomen during examination. She was euthanized at 2:10 pm and sent in for

necropsy.

Histopathology:

Uterus:  The myometrium was infiltrated by a neoplasm composed of epithelial cells forming tubules and acini.

Uterine wall: The myometrium is invaded by a neoplasm forming acini (neoplastic endometrial glands)

Uterus: Closer view of neoplastic endometrial glands, the neoplastic cells are separated by fibrous tissue

Uterus: Close up of neoplastic cells

Lung and Liver:  The neoplastic cells in the lung and liver resembled those in the uterus, however they formed solid sheets rather than acini and were more anaplastic with marked anisocytosis and anisokaryosis.

Lung: Low power view showing multiple individual nodule of metastatic uterine adenocarcinoma

Liver: A nodule of metastatic neoplastic cells compresses adjacent liver tissue

Comment:

Uterine adenocarcinoma arises from endometrial glands, and is the most common spontaneous neoplasm in Rabbits.  The incidence of this neoplasm increases to 80% of animals 5-6 years and older in Oryctolagus cuniculus. The etiology of the neoplasm is unknown, however some reports implicate estrogen as a related factor.  A recent report in Vet Pathol found that papillary adenocarcinomas were negative for both estrogen and progesterone receptors, but tubular/solid neoplasms were positive for either estrogen or progesterone receptors.  The authors suggest that there may be a separate pathogenesis between these two forms of the neoplasm.

These tumors usually are multinodular and involve both uterine horns.  They may metastasize to the lung and liver most commonly and become  implanted on serosal surfaces of the abdominal organs.

Reference:

Percy, DH and Barthold, SW. Chapter 6 Rabbit in Pathology of Laboratory rodents and rabbits, 3rd edition.  p 253.  Blackwell Publishing, 2007.

M. G. Asakawa, M. H. Goldschmidt, Y. Une, and Y. Nomura. The Immunohistochemical Evaluation of Estrogen Receptor-{alpha} and Progesterone Receptors of Normal, Hyperplastic, and Neoplastic Endometrium in 88 Pet Rabbits. Vet Pathol March 2008 , 45: 2: 217-225, doi:10.1354/vp.45-2-217.

Epidural steatitis and vertebral osteomyelitis in a dog

 

History:  A 1 year old spayed female bulldog mix canine became acutely non-ambulatory, and both rear limbs were hyporeflexive.

Gross Necropsy:

There was a 7 cm x 3 cm x 3 cm abscess in the epaxial musculature of the lumbar spine containing red-brown purulent fluid. The muscles surrounding the abscess including the epaxial and hypaxial musculature was pale, and there was a focal area of lysis of the ventral cortex of vertebral bodies L2 and L3.

Lumbar epaxial muscles: Abscess over spinal column

The dura of the spinal cord from vertebral bodies L2-L5 was covered with a thick layer of organized fibrin and suppurative material causing compression of the spinal cord. There were no gross lesions in the intervertebral discs and spinal cord.

Spinal cord: There is a thick mat of fibrinous and suppurative exudate lying on the spinal cord

There were multifocal 3-5 mm round red nodules diffusely throughout the

lung.

There was a 7 cm x 3 cm x 3 cm abscess in the epaxial musculature of

the lumbar spine containing red-brown purulent fluid. The muscles

surrounding the abscess including the epaxial and hypaxial musculature

was pale, and there was a focal area of lysis of the ventral cortex of

vertebral bodies L2 and L3. The dura of the spinal cord from vertebral

bodies L2-L5 was covered with a thick later of organized fibrin and

suppurative material causing compression of the spinal cord. There were

no gross lesions in the intervertebral discs and spinal cord.

There were multifocal 3-5 mm round red nodules diffusely throughout the lung.

 

Lung: Multifocal embolic pneumonia

 

 

Histopathology:

Epidural adipose:  The epidural fat is infiltrated by large numbers of neutrophils, macrophages, lymphocytes and plasma cells with large amounts of fibrin and fibrous tissue.  There are multiple bacterial colonies.

 

Spinal cord, dura and epidural adiopse- Suppurative steatitis

 

Vertebrae:  The cortical bone is infiltrated and lysed by a large amount of neutrophils, macrophages and fibroblsats.  There are large numbers of neutrophils surrounding bacterial colonies in the bone marrow of several vertebrae.

 

Vertebrae: Suppurative osteomyelitis with bacterial colonies

 

Bacterial colonies are composed of mixed gram positive rods and gram negative bacteria with the gram positive rods predominating.  Similar bacterial colonies are present in the lungs and valvular thrombus.

 

Gram stain of bacteria- Large numbers of gram positive rods consistent with Campylobacter spp

Aerobic culture:  A swab from the exudate covering the spinal cord grew Corynebacterium spp and an unidentified bacteria.

 

Lung: Embolic suppurative pneumonia with bacterial colonies

 

Diagnosis:

1. Spinal Cord: Fibrinosuppurative epidural steatitis, chronic, focally extensive with compression of spinal cord 

2. Vertebral body:  Suppurative osteomyelitis with bacterial colonies

3. Lung: Multifocal suppurative pneumonia

4. Heart, right AV valve: Focal valvular endocarditis (not pictured)

 

Comment:

Microscopically the spinal column lesions are more chronic as evidenced by increased numbers of macrophages, lymphocytes, and fibroblast proliferation.  Epidural steatitis can occur through direct extension of bacteria into the epaxial musculature or through hematogenous bacterial emboli.  The infection spread into the vertebrae and epidural adipose tissue causing spinal cord compression and the neurologic signs noted in the history.  Secondary bacteremia caused valvular endocarditis and embolic pneumonia.

Coccidiosis in a Chukar

History:   The flock is healthy in the brooder house, but 3-4 weeks after being turned out 2-5% of the birds get weak, thin, and listless.

Gross Lesions:  The two birds were in good body condition with no pectoral muscle atrophy.  No lesions of any significance were found.

Histopathology:

Small intestine:  There are abundant intracellular coccidia in varying stages of development in the enterocytes of multiple small intestinal sections. There is also segmental enterocyte necrosis with villous blunting in several sections of small intestine. In some sections coccidian oocytes are seen in the lumen of the small intestine among sloughed epithelial cells and necrotic debris.

 

Small Intestine: Numerous villous enterocytes contain large coccidial organisms

Small Intestine: Closer magnification, showing more detail of the coccidia

 

Small Intestine: High power view showing different stages of coccidia

 

Small Intestine: High power view

Morphologic diagnosis:  

Small Intestine: Villous enterocyte necrosis and villous blunting, severe,  segmental with intralesional intracellular coccidia

Comment:

We considered these birds to be in the early stages of coccidiosis, since there was no obvious weight loss, diarrhea or enteritis.  The infection was localized to small sections of the small intestine, but was severe in those sections.

Coccidiosis in Chukars can be caused by  Eimeria legionensis.

Life cycle of Eimeria:

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