A rare case of cystic renal cell carcinoma in a sheep

An eight-month-old ram lamb was presented to the Department of Veterinary Pathology, College of Veterinary Science, Proddatur, for necropsy with the history of anorexia, dyspnea, lethargy and emaciation. The post-mortem examination revealed clear serous fluid in the abdominal cavity, pale liver with a distended gall bladder, and enlarged, pale, pulpy kidneys with multi focal white necrotic areas on their surface. Cytological evaluation of kidney impression smears showed clusters of cuboidal epithelial cells, along with degenerative neutrophils, lymphocytes, and a few bipolar microorganisms. The neoplastic epithelial cells exhibited anisocytosis, homogenous bluish cytoplasm and large, pleomorphic nuclei with 3-5 prominent nucleoli. Mitotic figures were observed in the nuclei. Additionally, a few macrophages and multinucleated cells were found within the neoplastic clusters. Histopathological examination revealed diffusely dilated and cystic tubules, proliferation of tubular epithelial cells, infiltration of lymphocytes and degenerated neutrophils. Focal areas of glomerular dilatation were also observed. The tubular epithelial cells appeared polygonal to cuboidal, with basophilic cytoplasm and pleomorphic, dense nuclei containing prominent nucleoli. A few mitotic figures were also noted. Based on the gross, cytological and histopathological findings, the case was diagnosed as "Cystic Renal Cell Carcinoma" which is a rare neoplasm in sheep.