Uterine Polyp in a Rat

Uterine Polyp in a Rat

History:  A two year old black and white female intact rat with chronic non-responsive skin lesions.  

Gross Pathology:

In this case there was multifocal ulcerative dermatitis (not shown)


Uterus:  Filling the uterus is a pedunculated mass of mature collagenous connective tissue with sparse number of fibroblasts covered by endometrial epithelium.


Uterus with polyp

Uterus with polyp



Close up

Close up



Endometrial lining

Endometrial lining



Well differentiated fibrous stroma

Well differentiated fibrous stroma




This is a fairly common lesion in aging rats.  Polyps can be adenomatous or primarily stromal like in this case.  There are usually small to moderate numbers of neutrophils, lymphocytes and plasma cells infiltrating the polyp.

Ulcerative dermatitis is commonly caused by Staphylococcus aureus in rats.



Mor, N and Lutsky, I. Spontaneous endometrial tumours of ‘Sabra’ rats. Laboratory Animals (1986) 20, 316-320.

Percy, DH and Barthold, SW. Pathology of Laboratory Rodents and Rabbits, 3rd edition. Blackwell Publishing Professional , Iowa, 2007.


About Brian

Anatomic Pathologist, VetPath Services, Stone Ridge, NY- musculoskeletal, oral/dental, and sinonasal diseases
This entry was posted in Necropsy Cases and tagged , . Bookmark the permalink.

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