Renal Cell Carcinoma in Two Siberian Hamsters (Phodopus sungorus)

Renal cell carcinoma was diagnosed in 2 Siberian hamsters (Phodopus sungorus). One hamster had a unilateral solitary papillary-tubular carcinoma. The other hamster had a clear-cell, a papillary-tubular, and mixed types of carcinomas in the left kidney and a cystic-papillary-tubular type of carcinoma in the right kidney. In the papillary-tubular carcinoma. there were cuboidal to columnar cells arranged in tubular or papillary patterns supported by delicate fibrous stroma. Nuclei were located basally, often perpendicular to the subjacent basement membrane. Cytoplasm was pale to eosinophilic and variably abundant. Pleomorphic oval to polygonal cells found in the clear-cell carcinoma were arranged in broad trabeculae, lobules, or nests, with congested capillary stroma and multifocal necrosis. Cytoplasm varied from eosinophilic and granular to pale and clear or vacuolated. In the cystic-papillary-tubular carcinoma, cuboidal to columnar cells were arranged in cystic, papillary, or tubular patterns. Cysts varied in size and shape and contained secretory material and erythrocytes.