Unilateral erythromelanosis follicularis faciei et colli.

Clinical features and histopathologic findings are described in this case of erythromelanosis follicularis faciei et colli in a 30-year-old man of Chinese descent. This is the fourteenth case in the world literature and the first which is unilateral. Electron microscopic examination revealed abnormalities consisting of a homogeneous mass of pigment in the center of the melanosome and a stippled appearance to the periphery of the organelle. In addition, many of the melanosomes appeared to be abnormally large.

Stimulation of pigmentation in melanoma cells by trimethylpsoralen in the absence of ultraviolet irradiation.

The effects of trimethylpsoralen and 8-methoxypsoralen on the pigmentary characteristics of cultured murine melanoma cells were investigated in the absence of ultraviolet irradiation. Stimulation of pigmentation was assayed by gross examination of centrifuged cell pellets, light microscopy of cells, electron microscopy, a biochemical determination of cell tyrosinase activity, and a chemical determination of cell melanin content. It was found that an adequate concentration (10(-5) M) of trimethylpsoralen for an adequate exposure time stimulated pigmentation in the dark, whereas 8-methoxypsoralen in the same experimental setting did not stimulate pigmentation.

Amelanotic lentigo maligna melanoma manifesting as a dermatitislike plaque.

A 72-year-old man with a previous history of an amelanotic melanoma on his left forearm had an erythematous plaque excised from his right shoulder. Although the clinical impression was a dermatitis, a biopsy specimen revealed an amelanotic lentigo maligna melanoma. To our knowledge, this is the first patient described with an amelanotic lentigo maligna melanoma as a second primary tumor to an apparent previous amelanotic melanoma, manifesting as a dermatitislike plaque.