PURELY EPITHELOID SCHWANNOMA - 2 CASE-REPORTS AND A REVIEW OF THE LITERATURE

The authors describe 2 cases of purely epithelioid schwannomas, one sp inal the other peripheral. At surgery, the spinal schwannoma appeared as an orange-sized, solid, brown mass. Total removal of the tumor was performed. The peripheral schwannoma appeared as a fusiform, brown, mo vable mass in the sensitive branch of the left tibial nerve and was re moved by a wide en bloc excision. Intraoperative nerve action potentia ls were performed both prior to and following excision of the lesion. Histologically, the tumors were composed of round or polygonal cells a rranged in necrotic clusters and anastomosing cords. There were areas of spindle cells. The epithelioid cells were round to oval with abunda nt cytoplasm. Mitoses were frequent (3 out of 10 in high-power field). S100 protein immunoreactivity was present diffusely in tumor cells (b oth nuclear and cytoplasmic), whereas cytokeratin, NSE, and anti-melan oma reactions gave negative results. After a long follow-up, the neuro logical condition of the patients is excellent and there are no signs of either recurrence or metastasis. The therapeutic management of epit helioid schwannoma is discussed.