A multifocal neurinoma of the hypoglossal nerve with motor paralysis confirmed by electromyography

A rare case of neurinoma in a 72 year-old Japanese woman derived from the hypoglossal nerve is reported. The tumour was composed of three interconnected nodules occurring simultaneously in the left submandibular and sublingual regions. The lesion, which presented as a neck mass, caused a slight left-sided hemiparesis of the tongue with tongue deviation to the affected side not noticed by the patient. An electromyographic (EMG) study revealed decreased muscle activity on the left side of the tongue muscle, indicating dysfunction of the hypoglossal nerve. EMG was useful for diagnosis.