Golf ball near elbow: a rare presentation of a giant ulnar nerve Schwannoma

Abstract

Schwannoma is a type of peripheral nerve sheath tumor but can produce a mass effect with increase in size, spontaneous pain, paresthesia and motor weakness being the main complaints. A 60-year-old male patient presented with swelling in the left forearm since the past 8 months and numbness and tingling sensation in the hand for 1 month. Examination revealed a solitary lesion in the ulnar aspect of left proximal forearm with glove and stocking type of neuropathy, wasting of hypothenar eminence and amputation of left 5th digit, with hypopigmented lesions over the forearm and leg. Slit skin smear and biopsy of hypopigmented lesion was done to rule out leprosy. Ultrasonography (USG) and contrast-enhanced magnetic resonance imaging (CE-MRI) of left forearm lesion revealed homogenously enhancing lesion involving the proximal portion of left forearm - suggestive of peripheral nerve sheath tumor. Hence the patient was treated with excision and biopsy. Histopathological examination revealed a giant Schwannoma (6×4×3.5 cm) of the ulnar nerve with typical findings of spindle shaped cells few verocay bodies. Despite rare, tumors should be taken into account in the differential diagnosis in such presentations. It is important to remember that Schwannoma, in these cases, is the most common tumor. The simple removal of the tumor after careful dissection is generally enough since the recurrence and malignant transformation rates are low.