Ancient schwannoma of the median nerve­a case report and review of the literature of nerve tumors

Abstract

Schwannomas are known as neurilemmonas, the most common benign tumor of the peripheral nerve's neural sheath, arising from the Schwann cells derived from the neural crest. They are the commonest tumor of the peripheral nerves, 5% of which occur in the adults. 19% of the tumors occur in upper extremities and 45% of schwannoma occur in the head and neck and 13.5% in the lower limbs. Volar surface is affected more than the dorsal aspect and they may occur as multiple lesions or they may affect different nerves in the same extremity. Despite the classical description that schwannomas are well encapsulated and can be completely enucleated during excision, a portion of them have fascicular involvement and could not be completely shelled out. 75% of schwannoma of the upper extremity occur at elbow or distal to it. It occurs more in the mixed nerve instead of pure sensory or motor nerve. 50 %of patients have mixed nerve involvement. An important variant of schwannoma with degenerative changes are termed as Ancient schwannoma. This assumes significance since this may be confused with malignancy in both imaging and in histological studies. A clear understanding is crucial to the treatment plan for nerve tumors. We report a rare case of ancient schwannoma of the median nerve and take a review of the peripheral nerve tumors. pguygv neural sheath, arising from the Schwann cells derived from the neural crest (1) They are present as a painless swelling along the course of the nerves for a long time. They are the commonest tumor of the peripheral nerves, 5% of which occur in the adults (2). 19% of the tumors occur in upper extremities.(3) and 45% of schwannoma occur in the head and neck and 13.5% in the lower limbs. Discomfort may be the only complaint of the patient. Paraesthesia may be elicited on tapping of the swelling. The swelling may be misdiagnosed as ganglion, lipoma or lymph node. The tumors are round or ovoid, eccentric and well encapsulated. They are usually 2.5cm in size but they may grow up to 4­5 cm. The tumor is grayish, pink, yellow, brown or white in color. They are solitary and found along the anterior aspect of the extremities by the side of the nerves. Ancient schwannomas are a variant of schwannomas of long duration with degenerative changes. In long standing tumors the cut section may show variegated appearance and degenerative changes. The histological and radiological picture resembles that of malignancy but they are benign lesions. This case is reported for the rare nature of the ancient schwannoma of the median nerve and to analyze the surgical options available. II. Material and methods 2.1 case report A 75 years old lady presented with a painless swelling in the right cubital fossa of 10 years duration with complaints of increase in size of the swelling associated with pain for the past one year. She complained of pain and Paraesthesia in the median nerve distribution area of the right hand. She has numbness of the right hand with weakness in performing her day to day activities. There was atrophy of the Thenar muscles. The swelling measured 3.5 cm in length. The swelling was mobile on the transverse axis and not on the longitudinal c{kv .Tjgug zcv oqwqu zgcmpgvv cnvq. Pguexvvkqp qygu wjg pguyg ruqfxegf rqvkwkyg Tkpgnv vkip. Tjgug zcv nqvv of sensation in the distribution of the median nerve in the hand. The patient refused to undergo MRI examination due to economy reasons. A surgical workup and a pre­operative anesthetist assessment were obtained. With a clinical diagnosis of median nerve tumor the patient was planned for excision of the tumor. It was explained to the patient regarding the neurological deficit following the surgery and she may need a sural pguyg iuchw. Skpeg wjg rcwkgpwv