A Canine Case of Malignant Peripheral Nerve Sheath Tumor

Abstract

A tumor mass 10×8×5cm in diameter, arising at the retrapolathalmic temporal region of a 17-year-old female mongrel dog, was examined histopathologically and diagnosed as malignant peripheral nerve sheath tumor. The mass consisted of solid proliferation of spindle-shaped neoplastic cells showing fascicular arrangement with some myxomatous stroma or abundant collagen deposit. Metastasis was seen in the local lymph nodes. Some tumor cells were immunohistochemically positive for S-100 protein, and electoron microscopy revealed the tumor cells had desmosomes and a severely atypical nucleus.