Schwannoma of median nerve: Case report and review of literature

Abstract

Schwannoma of the median nerve is uncommon. It can be mistaken for other benign swellings. A 59- year- old lady presented with a slowly increasing swelling on the thenar aspect of left hand. She had pain and numbness. Tinel's sign was positive. MRI showed an intensely enhancing, ovoid swelling eccentrically to the median nerve. There was heterogeneity on T2-weighted image and on contrast enhanced sequence. Contrasting central and peripheral intensities is known as the target sign. Surgery was done with local anaesthesia under operating microscope. Dissection was done between the fascicles and the tumour wall. The tumour was excised. Histopathological examination showed spindle cells, with Antoni A and Antoni B areas, Verocay bodies and ectatic blood vessels. Immunohistochemistry showed positivity for S-100. Ki-67 index was 1–2%. The diagnosis was schwannoma. Postoperatively she was relieved of numbness. Keywords: Benign peripheral nerve sheath tumour, Median nerve schwannoma, Tinel's sign, Target sign, Antoni A area, Antoni B area