LARYNGEAL MELANOSIS - REPORT OF 4 CASES AND LITERATURE-REVIEW

OBJECTIVE: Laryngeal melanosis is a rare condition defined by the pres ence of melanocytes within the laryngeal epithelial lining. Our aims w ere (1) to review our cases together with those in the literature, and (2) to determine whether melanocyte incidence is increased with expos ure to irritant stimuli such as tobacco. METHODS: A retrospective stud y of ail cases diagnosed with laryngeal melanosis in our hospital from January 1, 1990, to December 31, 1996, was accomplished, Po determine the melanocyte incidence in the normal larynx as well as the influenc e of tobacco in development of laryngeal melanosis, 16 age-matched con trols, 8 of whom were smokers and 8 of whom were not, were chosen, and a histochemical and immunohistochemical study was performed. The foll owing antibodies were used: S-100 protein, CDla, and HMB-45. A compara tive study of the melanocyte incidence between patients with laryngeal melanosis and the controls was carried out. Also, a comparative study between smoking and nonsmoking patients was performed. RESULTS: Laryn geal melanosis was diagnosed in 4 patients at out hospital during this period of time, In the comparative study, the number of melanocytes i n the 4 patients with laryngeal melanosis was higher than in the 8 smo king (p < 0.01, Mann-Whitney U test) and 8 nonsmoking (p < 0.01) contr ols, and there was a trend toward a higher number of melanocytes in th e 8 smoking patients than in the 8 nonsmoking (p = 0.064) controls, CO NCLUSIONS: Laryngeal melanosis was more frequent in smoking men older than 50 years. Our observations underline the association of LM with l arynx carcinoma and ifs relation to a stimulus such as tobacco, in fac t, we have found activated melanocytes in our cases of laryngeal melan osis. They were identified by immunoreactivity for HMB-45.