A Schwannoma Originating from Median Nerve at Proximal Forearm Caused Ulnar Nerve Symptom by Compression

A schwannoma is a benign soft tissue tumor arising from the nerve sheath of a Schwann cell. Clinically, a schwannoma is an asymptomatic mass rarely causing neurologic deficits. However, it can cause discomfort as well as motor and sensory disturbances by compressing the nerve of its origin. The authors encountered a huge schwannoma arising from the median nerve at the proximal forearm, which caused symptoms mainly in the ulnar nerve. The tingling sensation along the ulnar nerve disappeared completely after enucleation of the schwannoma originating from the median nerve.