Primary malignant melanoma of the larynx.

Primary malignant melanoma of the larynx is a rare clinical entity. Only 53 cases have been reported in the medical literature to date. This report describes a case of primary malignant melanoma arising in the larynx and diagnosed by histologic examination of an excisional biopsy specimen. The patient was a 53-year-old man with a history of smoking and hoarseness. There was no clinical evidence of other primary malignant melanocytic lesions. Microscopically, the tumor consisted of polygonal-epithelioid cells admixed with more elongated, spindle-shaped cells. The majority of the cells demonstrated dark brown cytoplasmic and nuclear melanin. Marked pleomorphism and abnormal mitoses were also identified. Despite significant ulceration and disruption of the epithelium, in situ malignant melanocytes were recognized within the remaining portion of the epithelium. Immunohistochemical studies were positive for S100, HMB-45, and vimentin, while cytokeratin and iron stains were negative. Based on the clinical and histologic findings, a diagnosis of primary malignant melanoma of the larynx was established.