Granular cell tumour of the ulnar nerve in a young adult.

Granular cell tumours in peripheral nerve trunks are extremely rare. We report a case of a granular cell tumour of the ulnar nerve just distal to the elbow in a 16-year-old man. The appearance of the intraneural tumour could not be differentiated by magnetic resonance imaging (MRI) from more common nerve tumours. At exploration it was impossible to excise the tumour radically. Microscopic examination showed a clearly benign tumour and no malignant transformation has been found at follow-up after three and a half years.