ACRAL LENTIGINOUS MELANOMA - A HISTOLOGICAL TYPE WITHOUT PROGNOSTIC-SIGNIFICANCE

BACKGROUND. Acral lentiginous melanoma (ALM) is reported to have a poo rer prognosis than melanomas of other histotypes. OBJECTIVE. The purpo se of this paper is to verify if ALMs, per se, have a more aggressive behavior or if the poorer prognosis of these patients is due to a late r diagnosis. METHODS. Clinical charts of 165 patients with acrally loc ated melanoma were reviewed as well as all histological slides. In all patients, histotype, Clark's level, Breslow thickness, pigmentation, presence of ulceration, and regression were reported. Mitotic index, v ascular invasion, and microscopic satellitosis were also determined. S urival of the 64 patients with ALM was compared with survival observed in the remaining 101 acral (nonlentiginous) melanomas. RESULTS. Melan oma localized at acral sites constitute 8.9% of the 1845 patients with melanoma treated at our Institute from 1975 to 1990. All were Caucasi an, 57 were males, and 108 females. Out of the 165 patients with this localization, 64 (38.8%) were classified as ALM. Disease-free and over all survival of the 64 ALM patients were not different at a statistica lly significant level compared with the areas observed in the other ac ral non-lentiginous melanoma. CONCLUSION. The survival difference betw een ALM and other histological types is due to a later diagnosis and n ot to a more aggressive behavior of ALM.