Excision Depth and Prognosis in T1-T3 Plantar Melanoma: Is Complete Excision of Plantar Fat Pad Necessary?

While peripheral excision margins in cutaneous melanoma are well established, the optimal excision depth remains unclear. In plantar melanoma, the fat pad plays a key functional role, raising concerns about whether full excision is necessary for thin and intermediate-thickness lesions. This study evaluated the association between excision depth and oncologic outcomes in T1-T3 plantar melanoma.

Patients with primary T1-T3 plantar melanoma who underwent wide excision between 2008 and 2022 were reviewed. They were grouped by excision depth: intra-adiposal (partial fat pad preservation) and suprafascial (complete removal). Oncologic and functional outcomes, assessed via the Foot Function Index (FFI), were compared.

Ninety-four patients (40 intra-adiposal, 54 suprafascial) were analyzed (median follow-up, 43 months). Tumor-free margins were achieved in all cases. Baseline characteristics were similar, except for lesion location. Recurrence rates were comparable, and excision depth was not significantly associated with recurrence-free survival. FFI scores from 26 patients (13 per group) tended to be better in the intra-adiposal group, though not statistically significant.

In thin to intermediate-thickness plantar melanoma, intra-adiposal excision may be oncologically safe if tumor-free margins are achieved, potentially offering functional benefits without compromising oncologic outcomes.