Lentigo Maligna—Challenges, Observations, Imiquimod, Confocal Microscopy, and Personalized Treatment

The word melanoma imparts considerable fear and concern in patients. Fortunately, for patients with the lentigo maligna (LM) subtype of melanoma in situ, there is overall good prognosis. The challenge of LM, however, is that it has the highest rate of local recurrence (approximately 20%) of all melanoma subtypes when treated by standard surgical excision alone, owing to frequent, unpredictable, subclinical extension. To reduce this risk, the use of Mohs surgery or staged excision has consistently demonstrated lower recurrence rates of 0.3% to 2.2% yet requires larger surgical margins for histological clearance than other in situ melanoma subtypes. Moyer et al also demonstrated that with increasing lesion size, both the surgical margin required to clear the lesion and the risk of local recurrence increased, suggesting increased subclinical spread with increasing lesion size. In addition, LM is typically located in the head and neck area, a complex zone with potential cosmetic and functional impairment owing to extensive surgery. Finally, differentiating LM from background atypical melanocytic hyperplasia can be challenging. Thus, treatments directed toward reducing the extent of surgery, minimizing morbidity, and providing a cure would enhance patient outcomes.