AN ELECTRON MICROSCOPIC STUDY OF CHLOPROMAZINE PIGMENTATION

[摘要] Skin specimens of 5 Caucasian patients with chlorpromazine-induced, purplish hyper -pigmentation on the exposed skin were studied histochemically as well as by the electron microscope. Large, dopa-positive melanocytes were found in the basal layer, and all layers of the epidermis contained an increased number of melanin granules, accounting for a part of the hyperpigmentation. Melanin granules appeared normal, but there was an unusually large amount of fine particulate substance (premelanin granules) within the melanosomes. In the dermis a large number of melanin granules was found ingested in the lysosomes of large phagocytes. These phagocytes demonstrated a strong acid phosphatase activity but no dopa reaction. Round or bizarre-shaped dense bodies were found in the lysosomes of these large phagocytes as well as in the lysosomes of endothelial and perithelial cells of dermal blood vessels. These dense bodies were found in greater concentration in the pigmented areas than in non-pigmented abdominal skin and are thought to be related to metabolites of chlorpromazine. Although these dense bodies, related to chlorpromazine metabolites, could stimulate melanocytes to produce an abnormally large amount of melanin, it was, however, not clear whether or not these bodies were directly responsible for the purplish hyperpigmentation characteristically seen in these patients.