Surgical margins for lentigo maligna and lentigo maligna melanoma: the technique of mapped serial excision.

OBJECTIVES To assess the margins required for excision of lentigo maligna (LM) and lentigo maligna melanoma (LMM) by the technique of mapped serial excision (MSE), and to assess the efficacy of MSE. DESIGN An interventional, prospective, noncontrolled case series. SETTING Tertiary referral, dermatologic surgery unit. PATIENTS Consecutive patients with head and neck LM or LMM who underwent MSE between March 1, 1993, and October 31, 2002. INTERVENTION The MSE of LM or LMM. MAIN OUTCOME MEASURES The number of 5-mm levels for excision of LM and LMM and recurrence. RESULTS One hundred sixty-one LMs or LMMs in 155 patients were treated. Thirty percent (37 of 125) of LMs required more than 5-mm margins. For LMMs less than 1 mm in Breslow thickness, 12% (4/32) required more than 10-mm margins. For primary tumors, 20% of LMs (18 of 91) required more than 5-mm margins, while 10% of LMMs less than 1 mm in Breslow thickness (2 of 21) required more than a 10-mm margin. For recurrent tumors, 56% of LMs (19/34) required more than a 5-mm margin. Mean follow-up of 38 months (range, 5-100 months) showed 4 recurrences (2%) after MSE. The extrapolated recurrence at 5 years was 5.0%. CONCLUSIONS The current recommendations of 5-mm margins for LM and 10-mm margins for LMM less than 1 mm in Breslow thickness are often insufficient. Our results demonstrate the importance of margin-controlled excision, particularly in recurrent lesions. The use of MSE offers a high cure rate, in conjunction with tissue conservation.