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lentigo maligna

Wednesday 15 June 2011

Hutchinson’s melanotic freckle

The lentigo maligna (Hutchinson’s melanotic freckle), is an irregularly pigmented macule which expands slowly.

It should be noted that the recent WHO publication on tumors of the skin has stated that ‘lentigo maligna (LM) is a form of melanoma in situ …’.

There is great variation in color, with tan-brown, black, and even pink areas present. Perioral lesions rarely spread onto oral mucosa.

An amelanotic variant has been reported; rarely, this takes the form of an inflammatory plaque or follows cryosurgery or other therapy for lentigo maligna.

Progression to malignancy

The proportion of lentigo malignas that progress to lentigo maligna melanoma is said to be quite small, with a lifetime risk of only about 5%.

Invasive malignancy (vertical growth phase) is characterized by thickening of the lesion with the development of elevated plaques or discrete nodules.

Rapid progression to a deeply invasive tumor has been reported.

A contiguous solar lentigo is present in 30% of lentigo malignas and a pigmented actinic keratosis in 24%.