Lentigo maligna with spread onto oral mucosa.

BACKGROUND Lentigo maligna (LM) is a form of melanoma in situ most often seen in white patients on sun-exposed areas, primarily the head and neck. Spread of LM onto the conjunctiva has been reported. There have been no reports of LM extending onto oral mucosa. OBSERVATIONS We report 4 cases of LM in white women with contiguous spread from perioral areas to oral mucosa. The locations of the primary lesions were the vermilion of the lip, vermilion and perioral skin, cheek, and cutaneous aspect of the lip. Three cases showed focal histopathologic evidence of invasion during the course of the disease. The lesions ran a prolonged course characterized by repeated recurrences after surgery. Three of the cases required a complicated reconstruction after surgical excision. Mohs surgery with rush permanent (paraffin-embedded) sections resulted in a long remission in 2 cases, while in 1 patient, treatment with carbon dioxide laser was unsuccessful. CONCLUSIONS In a perioral distribution, LM can spread onto oral mucosa. This clinical presentation may cause significant long-term morbidity, as indicated by a high recurrence rate and/or progression to invasive melanoma. The oral mucosa should be examined in patients with atypical pigmented perioral lesions.