[Cutaneous pigmentation caused by amiodarone. Optical and ultrastructural study].

Thirteen biopsies from 8 patients with amiodarone-induced skin pigmentation were studied. Light microscopy showed that skin pigmentation of these patients was produced by solar elastosis, increase of melanin and accumulation of the properly called amiodarone pigment in the upper dermis. The degree of solar elastosis and the amount of amiodarone pigment was related to total doses of amiodarone. This pigment was negative for fat stains and positive for Masson-Fontana stain, and had neither birrefringency nor autofluorescence. Ultrastructurally, the granules of amiodarone pigment appeared as membrane-bound granules with a fingerprint-like lamellated structure, which others have related to lipofuscin. We conclude, however, that this pigment may be a metabolite of amiodarone, morphologically and histochemically related to melanin.