Spindle-cell variant of squamous carcinoma.A light and electron microscopic study of 13 cases

Abstract

Thirteen spindle-cell tumors of the upper respiratory tract, oral cavity, and skin of face have been studied with light and electron microscopy. Five were primary neoplasms, and 8 had recurred following radiation therapy. The primary lesions were superficially located, and, in light microscopic sections, sites of apparent continuity between tumor and overlying epithelium were observed. The electron micrographs demonstrated the presence in many tumor cells of aggregates of keratohyaline and slender bundles of tonofilaments, and occasional premelanosomes were seen. Desmosomes were present, but were few in number and poorly developed. No evidence could be found to support the concept of malignant connective tissue component. Findings justify designation of this group of tumors as spindle-cell variants of squamous carcinomas.