Mapped serial excision for periocular lentigo maligna and lentigo maligna melanoma

Abstract

Purpose To report the early cure rate for periocular lentigo maligna (LM) and LM melanoma (LMM), using modified Mohs surgery with vertically cut paraffin-embedded sections (mapped serial excision [MSE]). A secondary aim was to identify differences in the clinical features and outcomes between periocular LM and LMM and those found elsewhere on the head and neck. Design Prospective, noncomparative, interventional case series. Participants One hundred thirty-five patients undergoing 141 MSE procedures. Methods A prospective series of 141 MSE procedures for LM and LMM over a 10-year period (1993–2002) in a single-center Mohs surgical unit. Main outcome measures Recurrence, site, size of LM or LMM, invasiveness, prior recurrence, clear margin of excision, size of final defect, and number of levels required for complete excision. Results One hundred forty-one MSE procedures, of which 23% (32/141) were for LMM and 19% (27/141) were for periocular lesions. Location or prior recurrence were not predictive of invasive disease; however, the size distribution of the initial lesion ( P = 0.0354) and the final defect after MSE ( P = 0.0183) were larger in LMM. Thirty-one percent of LM and 14% of LMM less than 1 mm thick required larger than 5-mm and 1-cm margins, respectively, for complete excision. Mean follow-up of 32 months (range, 1–100 months) revealed 4 recurrences (3%), of which two were periocular ( P = 0.188). Conclusions Our review is the largest prospective series of MSE for LM and LMM and suggests that it is the treatment of choice in these forms of melanoma. Mapped serial excision offers a high early cure rate in conjunction with tissue conservation, which is of particular relevance in the periocular region. There were no significant differences between periocular LM and LMM and those found elsewhere in the head and neck region. It also appears that the current recommendations of 5-mm margins for in situ melanoma (LM) and 1-cm margins for melanoma less than 1 mm thick are insufficient for complete excision of LM or LMM, emphasizing the importance of margin-controlled excision of these lesions.