Mucoepidermoid carcinoma of the larynx: a light and electron microscopic study with emphasis on histogenesis.

Using light and electron microscopy, we recently studied a mucoepidermoid carcinoma of the larynx and reviewed 66 cases reported in the literature. Histologic features showed the origin of the tumor from the ductule of submucosal seromucous glands. The tumor was characterized by a mixed pattern of adenocarcinoma and squamous cell carcinoma. Six types of neoplastic cells were observed under the electron microscope, representing various stages of differentiation of the intermediate cells toward mucus-secreting, keratin-forming, and lumen-lining cells. The true incidence of this type of neoplasm could be higher than is believed because of its frequent misdiagnosis as squamous cell carcinoma. The importance of its differentiation from squamous cell carcinoma is emphasized because this tumor responds poorly to radiation therapy.