Granular cells in a cellular neurilemmoma.

In this article, we describe a case of a cellular neurilemmoma with focal granular cell elements. The Schwann cells showed S100 and Leu-7 immunoreactivity. The granular cells were periodic acid-Schiff-positive, diastase resistant with strong S100 immunoreactivity. Electron microscopy showed electron dense, heterogeneous granules in the granular cells and interdigitating processes and elongated nuclei of the Schwann cells. Although many granular cell tumors are believed to be derived from Schwann cells, neoplasms with both elements are rarely presented.