Treatment of atrophoderma of Pasini and Pierini-associated hyperpigmentation with the Q-switched alexandrite laser: A clinical, histologic, and ultrastructural appraisal

Background and Objective: Atrophoderma of Pasini and Pierini (APP) is an un common cutaneous disorder, with no known effective treatment, manifested by hyperpigmented patches that appear to be depressed compared with surroundi ng skin. This study investigated the effectiveness of the Q-switched alexan drite laser on a patient with extensive APP, and evaluated histopathologic and ultrastructural changes. Study Design/Patients and Methods: A man with stable APP underwent Q-switch ed alexandrite laser treatment to a patch on the trunk. Biopsies were obtai ned from treated and untreated sites of involvement. Light and transmission electron microscopic evaluation was performed to investigate melanosome nu mber, size, and volume, as well as melanin granule number and size. Results: After three treatment sessions, the treated area showed marked cli nical improvement. Electron microscopy showed a 19% reduction in melanin gr anule number and size and a 65% reduction in melanosome number, size, and v olume in larger melanosomes in treated compared with untreated sites. Conclusion: Treatment of APP with the Q-switched alexandrite laser results in clinical improvement. Electron microscopic evaluation suggests that the mechanism may be a reduction in the number, size, and volume of larger mela nosomes as well as a decrement in melanin granule number and size. Lasers S urg. Med. 27:206-212, 2000. (C) 2000 Wiley-Liss, Inc.