Light and electron microscopy of chlorpromazine-induced hyperpigmentation

Chlorpromazine may induce abnormal skin hyperpigmentation in exposed areas, described as slate-gray, purple, or blue-grayish discoloration. A 58-year-old man with schizophrenia, had been taking chlorpromazine for 5 years, and his sun-exposed skin areas exhibited a blue-grayish color. Large deposits of brown pigment and granular basophilic material were seen in the dermis with light microscopy. HMB-45 and anti-Melan-A antibody immunostaining labeled some pigment in the dermis. Transmission electron microscopy identified deposits among dermal collagen bundles collagen in both transverse and longitudinal sections. In the latter, an arboriform aspect of deposits was quite clear, and some melanophages were also seen. The three-dimensional examination of the dermis with scanning electron microscopy also identified deposits, which at higher magnification demonstrated an appearance in the shape of leaves, grass-like, interspersed with normal collagen. These results suggest a complex pathogenic mechanism, including deposition of dermal melanin together with drug itself and potentially additional unknown metabolites.