Schwannoma.

Abstract

Schwannomas are rare tumors. Since these tumors are derived from nerve sheaths and not from axons there is controversy regarding histogenesis and terminology. There is histological and histo-chemical evidence to consider that cells involved in the development of these tumors are schwannian cells and should be designated as schwannomas or neurilemomas, either benign or malignant. They are asymptomatic unless the lesion is large. The exact cause is not known.