"Pseudosarcoma" of the larynx.

Polypoid epidermoid carcinoma of the larynx with a cellular, often atypical stroma has also been classified as pseudosarcoma, carcinosarcoma, pleomorphic carcinoma, or spindle cell sarcoma. The nature of the spindle-shaped stromal cells has clinical significance, but pathologists do not agree about the origin and potential of these cells. This paper describes two laryngeal tumors, one with an abundant osseous component in which light-microscopic, ultrastructural, and clinical features suggest the origin of these fusiform cells from reactive pluripotential mesenchyme. In a second case, atypical fusiform cells within the stroma show ultrastructural epithelial characteristics. These findings suggest a varied histogenesis for pseudosarcoma of the larynx and may explain divergent theories expressed in the literature.