Lentigo Maligna Melanoma, In Situ

The development of eccentric pigmentation within a previously stable pigmented lesion may indicate malignant degeneration, as was the case here. Of all melanomas, lentigo maligna melanoma has the best overall prognosis.

An 82-year-old man complained about an asymptomatic “spot” on his chest within which a darker area had recently developed.

Key point: Physical examination revealed a large pigmented macule on the right upper chest. A darker area was eccentrically placed within the larger lesion. A biopsy revealed lentigo maligna melanoma, in situ.

Treatment: The lesion was removed by simple excision with a 5-mm border of normal skin.

Note: The development of eccentric pigmentation within a heretofore stable pigmented lesion may indicate malignant degeneration. There is some debate about the optimal border of normal skin to remove, with proponents of anywhere from several millimeters to nearly a centimeter. Lentigo maligna melanoma has the best overall prognosis among all types of melanomas.