Schwannoma of the left brachial plexus mimicking a cervicomediastinal goiter in a young Nigerian lady.

Abstract

The schwannoma is thought to arise from the schwann cells of the nerve sheath. This tumor is usually solitary and may arise from any cranial or peripheral nerve. It is encapsulated and appears to arise focally on a nerve trunk so that the nerve itself is stretched over the tumor rather than running through it as in neurofibroma. This report is unusual as the tumor started as a cervical swelling which subsequently grew into the mediastinum simulating a retrosternal goiter. The patient, a 25 year-old female was referred to the University College Hospital, Ibadan, 24 hours after an attempted thyroidectomy at a private hospital. The history was of a painless anterior neck swelling of 4 years duration devoid of symptoms of hyperthyroidism with associated dysphagia and weakness of the left hand. Examination showed an asthenic young woman. Her voice was hoarse but there were no eye signs suggestive of thyrotoxicosis. On the anterior neck was a sutured skin-crease scar over a diffuse anterior neck swelling which one could not get below. The left hand showed wasting of the thenar and hypothenar eminences. Thyroid function test results were within normal limits, indirect laryngoscopy showed a left vocal cord paralysis, packed cell volume was 38%. Her chest x-ray showed a huge left retrosternal and apical soft tissue mass displacing the trachea to the right (figure 1). A fine needle aspiration cytology was reported as a chronic lymphocytic thyroiditis. A presumptive diagnosis of thyroid carcinoma with retrosternal extension was made. At surgery, manipulation of the mass was difficult as the tissue was soft, slimy and ruptured easily. Severe hemorrhage was encountered necessitating a median sternotomy to control the bleeding vessels. Her post-operative period was stormy, however she thereafter made gradual progress to warrant her discharge six weeks post surgery.