Nasal schwannoma.

Schwannomas are most commonly located on the VIII CN(80%). They are more rarely found in the nasal region (4%). On the nose, they may rise from the autonomous nervous fibers or from branches of the V CN. Malignant transformation is rare (2%). According to Hillstrom1, electron microscopy and immunohistochemistry help in differentiating this tumor from neurofibromas, the latter with more common malignant transformation (12%). Nasal schwannomas may present progressive unilateral nasal obstruction, with or without epistaxis, hyposmia and headaches. On physical examination we usually only see a grayish mass in the nasal cavity. It may resemble a vegetative lesion or polyp, much vascularized and bleeding excessively. Nasofibroscopy and CT scan are necessary in order to assess tumor extension and surgical approach. Histopathology provides the final diagnosis. Treatment is based on total tumor excision. Pre-operative biopsy helps in the differential diagnosis of other nasalborn tumors.