Fibroma (myxoma) molle in a Hamster (Mesocricetus auratus)

An adult female Syrian hamster (Mesocricetus auratus) presented with a larg e, ulcerated lesion in its right cheek pouch; this wound interfered with th e animal's ability to masticate. As a result, the hamster became inappetant and lethargic and lost about 25% of its original body weight within 6 to 9 weeks of presentation. The mass was surgically excised and submitted for h istopathological evaluation. Microscopically, the mass was characterized as a neoplastic process partially encapsulated with fibrous connective tissue in the submucosa. Loosely arranged bundles of spindle to stellate cells wi th round to oval hyperchromatic nuclei and amphophilic cytoplasm were abund ant. Some cells had multiple nucleoli, and some mitotic figures were observ ed. Special stains were used to definitively diagnose fibroma (myxoma) moll e, a rare spontaneous neoplastic lesion in the hamster.