Photochemotherapy-induced lentigine on a vitiliginous patch. Electron microscopic observations

Patients with vitiligo seem to be less prone to the development of lentigines as a side effect of long-term photochemotherapy than do psoriatics. An 8-year-old boy who had a vitiliginous patch on his left thigh, had been receiving photochemotherapy since he was 2 years old. At the age of 3, multiple star-shaped, brownish macules developed at the site of treatment. Photochemotherapy was continued until the patient was 6 years old, at which time no improvement in the vitiligo was seen, so photochemotherapy was discontinued. Now 2 years after treatment the lentigines still persist. On electron microscopic examination, the melanocytes showed two patterns of cell death: coagulative necrosis and apotosis together with atypical cytoplasmic and melanosomal alterations.