Renal Adenoma with Hydronephrosis in a Cat

A 6-year-old castrated male domestic short hair cat with the clinical signs of anorexia and vomiting was admitted to the local animal hospital. Abdominal radiography and ultrasonography revealed renomegaly and severe hydronephrosis in the right kidney. Surgically excised right kidney was submitted for diagnosis. On the cut surface, two milky white masses and severe dilation of renal pelvis were observed. Most of the neoplastic masses were composed of uniform well differentiated tubules lined by a single layer of cuboidal to columnar cells and projected papillae into the lumen. The neoplastic cells were strong positive for cytokeratin (CK) MNF116, but negative for CK 7. Based on the clinical and gross findings, histopathology and immunohistochemistry, this case was diagnosed as papillary renal adenoma with hydronephrosis.