A 64-year-old Japanese woman had a lightly brown-blackish pigmented macule (1.2 cm in diameter) on the left sole of her foot. She received surgical excision following a diagnosis of acral lentiginous melanoma (ALM), which was confirmed histopathologically. One month after the operation, a second melanoma lesion was noticed adjacent to the grafted site. Histopathologically, the two lesions had no continuity, but HMB-45 and cyclin D(1) double-positive cells were detected not only on aggregates of atypical melanocytes but also on single cells near the cutting edge of the first lesion. The unique occurrence of a sequential lesion of a primary melanoma might be caused by stimulated subclinical field cells during the wound healing process following the initial operation. This case warrants further investigation to establish the appropriate surgical margin of ALM lesions.
Keywords: Acral lentiginous melanoma; Cyclin D1; Field cell model; Melanoma spread; Primary melanoma; Surgical margins.