Re-excision is the best treatment for lentigo maligna with non-clear margins, especially with peripheral zone lesions, according to study findings published in the Annals de Dermatologie et de Vénéréologie. Even with clear margins, risk of lentigo maligna recurrence warrants close follow-up.

With worldwide increase in occurrence of the most common melanoma in head and neck areas (most frequent in older patients with sun-damaged skin), the multifocal lentigo maligna creates risk for incomplete removal and a potential recurrence, and progression of an invasive tumorous component lentigo maligna melanoma (LMM). Researchers sought to distinguish characteristics associated with invasive forms of lentigo maligna and the dynamics associated with its recurrence. The primary objective was identification of clinical factors in lentigo maligna associated with primary invasive lesions.

They conducted a single-center, retrospective study of 175 consecutive patients with lentigo maligna (N=99) and lentigo maligna melanoma (N=76) (median age at diagnosis 72 years; 51%women) treated via surgery from 2009 through 2014. They found lesions were more likely to reside in the peripheral zone (neck, ears, temple, ,scalp) in men (41.8%) and more commonly in the central zone (face and forehead) in women. Analysis showed only the peripheral zone to be associated with risk for invasion.


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Recurrence rate was 9% and lesions were most likely primary lentigo maligna melanoma excised with clear margins. About 18% of patients were under 60 years of age, and about 25% of patients had undergone previous treatment. Neither age nor lesion size associated with invasive risk, indicating patients with lentigo maligna and lentigo maligna melanoma have similar lesions. Even with biopsy, invasion was underestimated in more than 20% of cases. Peripheral area lesions dictate a goal of clear margins, and central zone lesions may allow surgical alternatives in radiotherapy or imiquimod.  

Researchers said in conclusion, that, “The treatment of choice in [lentigo maligna] with non-clear margins must be re-excision, especially for lesions situated in the peripheral zone.” Given the risk of recurrence even with clear margins, they urge close follow-up. They added, “Such recurrence occurs most often in patients with [lentigo maligna/ lentigo maligna melanoma] initially excised with healthy margins,” underscoring the urgency of clinical follow-up.

Reference

Gérard E, Cogrel O, Goehrs C, et al. Clinical features associated with the invasive component in lentigo maligna of the head and neck: A retrospective study of 175 cases. Ann Dermatol Venereol. Published online June 20, 2022. doi:10.1016/j.annder.2022.03.008