Lingual Malignant Peripheral Nerve Sheath Tumor in a Chinese Pug Dog.

A 9-year-old spayed/female Chinese Pug dog presented for evaluation of a mass located on the rostral aspect of the tongue. An incisional biopsy was acquired, submitted, and interpreted as a possible granular cell tumor based on hematoxylin and eosin, and periodic acid Schiff histopathologic staining characteristics. The diagnosis was supported by immunohistochemical evaluation that was positive for S-100, vimentin, and neuron-specific enolase. Based on the absence of mitotic figures in the incisional biopsy, a partial glossectomy was performed with gross margins of at least 1-cm. The excisional biopsy revealed significant features of malignancy, with neoplastic cells in close association with peripheral nerves, consistent with malignant peripheral nerve sheath tumor. Tumor-free margins were obtained, and the glossectomy had expected healing with no recurrence apparent 6-months following surgery.