Bilateral Plexiform Neurofibromas of the Posterior Interosseous Nerve Mimicking Dorsal Wrist Ganglions.

A 33-year-old woman presented with bilateral dorsal wrist masses associated with pain and limited range of motion. On initial presentation, the masses were believed to be ganglion cysts and the patient opted for observation. Three years later, she was found to have a chest wall mass diagnosed by biopsy to be a neurofibroma. When she later returned to seek treatment for her wrist masses, magnetic resonance imaging demonstrated posterior interosseous nerve (PIN) neurofibromas. Dorsal wrist masses situated over the scapholunate interval are commonly attributed to ganglion cysts. Neurofibromas of the PIN, although rare, should be considered in the differential diagnosis when a mass elicits pain with percussion, fails to transilluminate, fails aspiration, or if the patient has a history of neurofibromas elsewhere in the body.