Lamellar bodies in benign and malignant schwannomas.

A light and electron microscopic study was done on seven cases of schwannomas, four of which were benign and three were malignant. Spherical or oval cytoplasmic inclusion bodies, one to three microns in diameter, were detected in all cases. These inclusions were demonstrable by Luxol fast blue stain. Ultrastructurally, the inclusions appeared as whorls of cell membranes reminiscent of myelin sheath. These lamellar bodies probably reflect the peculiar membrane characteristics of Schwann cells, and they provide a useful marker for recognition of benign or malignant schwannomas.