Malignant peripheral nerve sheath tumor of the lower labial mucosa: case report and literature review.

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon soft tissue sarcoma with a predilection for the extremities and trunk of adults, rarely occurring in the oral cavity. To date, 10 cases of MPNSTs affecting the lower labial mucosa have been reported in the English language literature. We describe an additional case of MPNST in the lower labial mucosa of a 67-year-old male patient, who exhibited a painful swelling with a history of 4 months of evolution.