[A rare cause of forearm pain: Schwannoma of the posterior interosseous nerve].

A schwannoma, also known as a neurilemoma, is composed of Schwann cells, and is the most common benign tumor of the peripheral nerves. It commonly appears as a solitary lesion in the head and neck region. The diagnosis is based on ultrasonography, magnetic resonance imaging, and histopathological examination. This encapsulated tumor has a good prognosis with a low recurrence rate after surgical removal. This case report is a description of a forearm schwannoma that initially appeared to be a ganglion cyst.