Abstract
We present a 59-year-old man with a 3-year history of pigmented macule on the left sole. Physical examination revealed a 24-mm in diameter, relatively welldemarcated, irregularly-shaped, black-brownish variegated hyperpigmented macule on the left sole. Neither elevation nor infiltration was noted. After a clinical diagnosis of acral lentiginous melanoma (ALM) in situ was made, the lesion was totally excised with a 10-mm margin above the fascia level, and the wound was covered with full-thickness skin graft. No elevation of 5-S cysteinyl dopa in his urine and blood before and after the operation was determined. Histopathological findings of the center of the lesion showed an increased number of melanocytes with minimal atypia and basal hyperpigmentation. The immunohistochemical staining against HMB-45 was negative. We further prepared sections from the darkest hyperpigmented area, lightly-pigmented area and moderately-pigmented area. The darkest area showed the significant increase of atypical melanocytes, forming small nests with basal hyperpigmentation and pigmentary incontinence. These findings collectively confirmed the diagnosis of ALM in situ. The present case suggests the importance of histological examination from multiple locations, corresponding to the macroscopic degrees of hyperpigmentation. [Skin Cancer (Japan) 2002; 17: 148-152]
