Epithelioid schwannoma: diagnosis by electron microscopy

The clinical, gross, and light microscopic features of two epithelioid tumors were not typical of either benign or malignant schwannoma. Both tumors displayed long, enveloping cytoplasmic processes that were outlined by layers of discrete basal lamina. Long-spaced collagen was found in one case. These well-developed electron microscopic features are those that are commonly encountered in benign Schwann cell tumors. Although one patient died postoperatively, the other is alive and well 12 months after surgery. The extent to which ultrastructural data can have an impact on the evaluation of Schwann cell tumors is unknown but requires further study.