Solitary dermal leiomyosarcomas in 12 ferrets.

Twelve 3-6-year-old ferrets (8 males, 3 females, 1 unknown) were presented with single cutaneous nodules. These dermal tumors were characterized histologically by nodular proliferation of neoplastic smooth muscle fibers with marked anisokaryosis and a mitotic rate of >2 mitoses per 10 high-power fields. Neoplastic cells stained strongly for vimentin in all tumors and for smooth muscle actin and desmin in all but 1 tumor. Histologic and immunohistochemical findings suggested a diagnosis of piloleiomyosarcoma for these tumors. Excision was curative in all animals available for follow-up. However, 3 of 5 animals developed adrenal disease within 7 months after removal of the dermal leiomyosarcoma.