Superficial neurofibromas in the setting of schwannomatosis: nosologic implications

First described in the past decade, schwannomatosis is a syndrome distinct from neurofibromatosis 2 (NF2). It is characterized by the development of multiple schwannomas, sparing the vestibular division of cranial nerve VIII, and may also predispose to develop meningiomas. We report two female patients, a 27 and a 44 years old who developed multiple peripheral schwannomas, but without involvement of the vestibular nerves, satisfying clinical criteria for schwannomatosis. Lack of vestibular nerve involvement was confirmed with MRI using an internal auditory canal protocol with 3 mm thick slices in both patients after age 30. Both patients developed a small neurofibroma in axillary subcutaneous tissues and a diffuse cutaneous neurofibroma of the left buttock, respectively. This report highlights that superficial neurofibromas may arise in the setting of schwannomatosis, which may have implications for the diagnostic criteria of this unique syndrome. In particular, the presence of a cutaneous neurofibroma in a patient with multiple schwannomas should not lead to a diagnosis of NF2.