Undifferentiated carcinoma of the salivary gland in a chinchilla (Chinchilla lanigera).

A 12-year-old chinchilla (Chinchilla lanigera) developed a slow-growing, soft, fluctuating, nonpainful mass on the ventral neck with focally extensive alopecia over a period of approximately 8 months. On postmortem examination, an extensive, multilobulated, cystic, neoplastic mass extended subcutaneously over the ventral and lateral neck with metastatic spread to submandibular lymph nodes, spleen, liver, and lungs. Neoplastic cells were strongly positive for vimentin and pan-cytokeratin but were negative for alpha-smooth muscle actin, S100, and myosin; no intracytoplasmic myofibrils were detected on phosphotungstic acid hematoxylin staining. Histologic and immunohistochemical examination of the mass led to a diagnosis of undifferentiated carcinoma of the salivary gland and contributes to the paucity of knowledge concerning neoplasia in chinchillas.