Surgical and histologic pitfalls in the management of lentigo maligna melanoma

Lentigo maligna melanoma (LMM) is a malignancy with increasing incidence, accounting for about 4% to 15% of all melanomas. Lentigo maligna (LM) is LMM in situ, usually presenting an irregular tan colored or brownish pigmented macular lesion persisting for years on chronically sun-exposed skin. Left untreated, LM may evolve into invasive form of LMM. Histologic evaluation of LM/LMM can be difficult due to widespread atypical melanocytes that are present in the area chronically sun damaged skin. It has been shown that chronically sun-damaged non-lesional skin can display some atypical features even in the absence of a melanocytic neoplasm. It is important for dermatopathologists to be aware of these findings so that such features are interpreted appropriately when making a histological assessment that may ultimately influence therapy and outcome. LMM is characterized by significant subclinical lesion extension which makes the treatment another challenge. Nowadays, a variety of therapeutic options are available in the treatment of LMM. Surgery remains the mainstay of LMM therapy, however the treatment of LM remains controversial subject in the literature. Non-surgical treatment modalities for LM include: destructive procedures such radiotherapy, cryotherapy, curettage, laser, electro-destruction and immunotherapy with the topical application of 5% imiquimod cream. These treatment options should be considered for a subset of patients with LM, especially in elderly patients with extensive or unresectable disease in difficult areas on the face or, as a second-line therapy if surgery is contraindicated. Surgical options include simple excision and margin-control techniques such as staged excision and Mohs micrographic surgery.In this article, authors are reviewing the latest diagnostic and therapeutic advances in the management of LMM.