Benign peripheral nerve sheath tumor of the tongue.

Peripheral nerve sheath tumors rarely occur in the oral cavity and include neurofibroma, schwannoma, and palisaded encapsulated neuroma. We report a rare case of benign peripheral nerve sheath tumor of the tongue. This tumor was a 0.8 X 0.5 cm sized, firm mass on the left lateral surface of the tongue. Histologically, this mass was composed of well- circumscribed variable sized nodules, which consisted of moderately cellular spindle cells with vague nuclear palisading and a small amount of fibrous tissue. Most of the tumor cells were strongly positive for S-100 protein, but negative for epithelial membrane antigen on immunohistochemistry. No axons were found by immunostaining for neurofilament and Bodian stains. In addition, the surrounding, compressed, fibrous tissue showed rare EMA- positive cells. The present case might be a rare case of neurofibroma arising in the tongue, although immunohistochemical and special stains did not support such a diagnosis.