Lentigo maligna/lentigo maligna melanoma: current state of diagnosis and treatment.

BACKGROUND: Lentigo maligna (LM) is a subtype of melanoma in situ that typically develops on sun-damaged skin. Presentation may be quite subtle and delayed diagnosis is common. Clinical margins are often ill defined. Histologic evaluation can be difficult due to the widespread atypical melanocytes that are present in the background of long-standing sun damage. Recurrence following standard therapies is common.

OBJECTIVE: To review the clinical features, histopathology, and treatment options for LM. Emphasis is placed on recent advances in the treatment of LM.

METHODS AND MATERIALS: Literature review.

RESULTS: The estimated lifetime risk of LM progressing to LM melanoma is 5%. Standard excision of LM with 5 mm margins is insufficient in 50% of cases. The recurrence rate with standard excision ranges from 8 to 20%. Mohs surgery and staged excision may offer better margin control and lower recurrence rates (4-5%). Estimates of recurrence rates following nonsurgical therapies such as cryosurgery, radiotherapy, electrodessication and curettage, laser surgery, and topical medications range from 20 to 100% at 5 years.

CONCLUSIONS: Adequate treatment of LM requires a comprehensive knowledge of the diagnostic features, histopathology, and treatment options. Surgical modalities with meticulous evaluation of tissue margins appears to offer the lowest rates of disease recurrence.