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.

Median nerve schwannoma

“…The ulnar and peroneal nerves are most frequently involved, whereas only 7% of schwannomas occur in the median nerve . Schwannoma may be associated with neurofibromatosis type 1, schwannomatosis or von Recklinghausen's disease . However, the presented case had no syndromic signs or symptoms.…”

“…Schwannomas are usually palpable, painless and solitary lesions . These tumours most frequently appear between 20 and 50 years of age, with similar incidence rates in males and females . Schwannomas can be readily separable from the surrounding tissue due to the presence of a true capsule.…”

“…Schwannoma and neurofibroma (NF) are two distinct types of peripheral nerve sheath tumour, of which schwannoma is the most common type (1%), accounting for 5% of all tumours in the upper extremity and 0.1–0.3% of all hand tumours . The ulnar and peroneal nerves are most frequently involved, whereas only 7% of schwannomas occur in the median nerve .…”

“…In all the cases, schwannoma was treated by surgical excision. Treatment by surgical excision is often curative …”

About a Rare Case of Chronic Ankle Pain: Unusual Localization of the schwannoma

“…[8] A. Goyal, "Benign and malignant tumors of the peripheral nerve," in Youmans and Winn Neurological Surgery, Elsevier, 7 edition, 2017, Chapter: 258. Histologically, the neoplasm is characterized by encapsulation and is composed of Antoni A and B cells and Verocay bodies [9] Immunohistochemistry shows that S-100 stain was positive [10] CONCLUSION Given that the chronic ankle pain is a frequent complaint of elderly patient, we emphasis that schwannoma should be considered as a possible diagnosis in patient with chronic ankle pain particularly if all other injury has been ruled out which can raises the awareness about this rare entity and so leading to an early diagnosis of schwannoma which may prevent permanent nerve damage, soft tissue or boney deformity. No gender predilection is noted.…”