Median nerve schwannoma: A case and review of literature

Abstract

We report a case of a median nerve schwannoma, a rare type of a benign tumor of Schwann cells that presents as a palpable and painful mass on the flexor aspect of the forearm. Schwannomas of the median nerve make up 0.1-0.3% of all hand tumors. Symptoms are caused by an entrapment syndrome resulting from the growing tumor. Pain is the most common complaint of schwannomas. Imaging studies include computed tomography and magnetic resonance imaging and ultrasound. It is difficult to differentiate schwanommas from neurofibromas solely on the basis of a radiological investigation. Tumors of the median nerve are diagnostically challenging and median nerve schwannomas are rare. Diagnostic pearls are described to facilitate a more accurate and timely diagnosis. These characteristics include mobility, Tinel's sign, S-100 histological staining, and Antoni patterns. With a correct diagnosis, the tumor can be extirpated with preservation of nerve function and a low risk of recurrence.

Keywords: Median nerve; Tinel's sign; schwannoma.

Figure 1

Schwannoma over flexor aspect of forearm

Figure 2

Schwannoma intact with median nerve

Figure 3

Median nerve after excision of schwannoma

Figure 4

Encapsulated schwannoma specimen

Figure 5

Histology of schwannoma with its characteristics pattern