The Bottom Line on Acral Melanoma

Acral lentiginous melanoma (ALM) accounts for 2% to 3% of all melanomas; however, many studies of this lesion have been small series from single institutions rather than nationwide surveys of clinical patterns. Bradford and colleagues recently examined ALMs using data from the NCI SEER registry. Between 1986 and 2005, the overall age-adjusted incidence rate of ALM was 1.8 per 1,000,000 person-years. By contrast, the per–1,000,000-person-year incidence rates of the other major melanoma histologic subtypes were lentigo-maligna melanoma, 12.0; nodular melanoma (NM), 12.7; and superficial spreading melanoma (SSM), 57.4. Thus, new ALMs occur roughly 1/50th as often as SSMs. ALM incidence increased from 1.6 per 1,000,000 person-years in 1992–1994…