Treatment of lentigo maligna (Review)

Abstract

Lentigo maligna (LM) is the most common type of in situ melanoma, usually appearing on chronically sun-exposed skin (mostly the head and neck) of elderly patients. It manifests clinically as a macule with a heterogeneous pigmentation and irregular contours. LM grows gradually over the years in a radial pattern and may eventually progress with a vertical growth phase, thereby transforming into an invasive melanoma (LM melanoma) that has potential for metastasis and a lethal outcome; accordingly, LM is currently regarded as an authentic melanoma in situ, rather than a premalignant condition. To the best of my knowledge, no prospective, randomized controlled studies evaluating the efficacy of the various treatment modalities applied for the treatment of LM exist to date. Surgical excision with tumour-free margins is regarded as the most effective treat- ment, achieving optimal rates of tumour clearance. Excision can be performed as traditional, one-step tumour ablation with predefined safety margins or, preferably, with margin-controlled techniques, such as staged excision or Mohs micrographic surgery, the latter methods achieving the highest cure rates. In the case of surgically-unresectable tumours or in frail patients with severe comorbidities, alternative non-surgical (off-label) therapies can be applied, including namely radiotherapy and imiquimod, as monotherapy or in various combinations.