Peripheral nerve sheath tumours--a short series with some uncommon variants.

Peripheral nerve sheath tumours are rarely malignant (0.001%), such malignant peripheral nerve sheath tumours (MPNST) are more common in upper extremities than in head and neck. Chondroid differentiation in benign peripheral nerve sheath tumours and melanotic schwannoma are very uncommon. In a retrospective analysis of 25 peripheral nerve sheath tumours over a period of two years, we reported two MPNST one of which was in a parapharyngeal location while the other MPNST showed melanotic differentiation. Similar melanotic differentiation was also seen in another benign melanotic schwannoma. Chondroid differentiation in a schwannoma was also observed which is usually documented in MPNST.