Acral Lentiginous Melanoma of the Hand: Diagnostic Pitfalls and Margin Management Strategies.

Acral lentiginous melanoma (ALM) is a rare but aggressive subtype of melanoma that can be easily missed. It may also be underresected during the first surgical excision, mandating additional surgery. An 81-year-old man presented with a pigmented lesion on the dorsum of the hand. Initial dermatologic treatment with cryotherapy failed, prompting an excisional biopsy, which revealed malignant ALM with a Breslow depth of 2.2 mm, with positive peripheral margins for ALM in situ. The patient underwent a second wide local excision and axillary sentinel lymph node biopsy. The nodes were negative for tumor. However, invasive ALM was found at the margins of the resected specimen. This necessitated a third wide local excision, incorporating the previous graft and surrounding tissues. Final pathology after the third resection confirmed negative margins. This case highlighted the locally aggressive nature of ALM, its potential for multifocal subclinical spread, and the need for thorough pathological and surgical strategies. The concept of multifocal invasion and field effect warrants attention in surgical planning.