Report of mammary fibroepithelial hyperplasia in a DSH cat

Fibroepithelial hyperplasia is a physiological change in mammary glands tissue characterized by a significant increase in the size of one or more mammary glands. The disease is commonly seen in healthy cats and may also be seen in older female cats. This report describes the clinical, radiographic, and microscopic features of a cat with fibroepithelial hyperplasia. A 4-year-old female cat weighing 2.7 kg with a large mass below the abdomen was referred to the veterinary hospital of Shahid Chamran University of Ahvaz. After clinical examination and radiological evaluation, he underwent surgery and the isolated mass was sent to the pathology department. The mass was solid and was observed at the incision of several lobules that had a walnut-like appearance. Under microscopic examination, proliferation of mammary duct epithelial cells and formation of new tubules were significant. Also, a large amount of connective tissue was observed around the formed tubes. Empty spaces were observed between the connecting strands, which indicated edema. It should be noted that no malignant changes were observed. In general, according to clinical, radiological and microscopic characteristics, fibroepithelial hyperplasia was diagnosed. The pathophysiology of fibroepithelial hyperplasia of the mammary gland is not well understood, but most likely sexual hormones play roles in etiology of fibroepithelial hyperplasia.