Acral lentiginous melanoma. A clinicopathologic entity.

Acral lentiginous melanoma (ALM) is the fourth clinicopathologic variant of malignant melanoma. It occurs on volar surfaces of hands and feet, subungual sites, and fingers or toes. It is characterized by slow lentiginous radial growth and central plaque-like thickening, heavily pigmented tumor cells, markedly thickened papillary dermis, and diffuse reticular infiltration. Lesions are unusually large and, in most cases, thick and ulcerated. There were 180 patients with acral melanoma (AM), which includes 67 in whom the specific features of ALM could be documented. One hundren sixty had primary lesions on ;the foot, and 20 occurred on the hand. There were 104 men and 76 women. There were 41 black patients and 139 whites. Five-year survivals following all modalities of therapy in 122 patients with Stage I acral melanoma is 63% for planter/palmar lesions, 58% for subungual lesions, and 27% for skin of digits. For the subgroup of Stage I patients with ALM treated by surgery and regional chemotherapy by perfusion, the five-year survival for all sites is 72% and 56% at 10 and 15 years, respectively. Survival in ALM is essentially the same as for all AM lesions.