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

Area of Science:

• Dermatopathology
• Histochemistry
• Pharmacology

Context:

• Amiodarone is a medication used to treat heart rhythm disorders.
• Skin pigmentation is a known side effect of amiodarone treatment.
• The exact nature of the pigment causing amiodarone-induced skin pigmentation requires further clarification.

Purpose:

• To investigate the histological and ultrastructural characteristics of amiodarone-induced skin pigmentation.
• To determine the relationship between amiodarone dosage and the degree of skin pigmentation.
• To elucidate the nature of the amiodarone pigment and its relationship to melanin and lipofuscin.

Summary:

• Light microscopy revealed that amiodarone-induced skin pigmentation is caused by solar elastosis, increased melanin, and the accumulation of a specific amiodarone pigment in the upper dermis.
• The extent of solar elastosis and amiodarone pigment accumulation correlated with the total dosage of amiodarone administered.
• Histochemical analysis showed the pigment was Masson-Fontana positive, fat stain negative, and lacked birefringence and autofluorescence.
• Ultrastructural examination identified the pigment as membrane-bound granules with a fingerprint-like lamellated structure, similar to lipofuscin.

Impact:

• This study provides a detailed morphological and histochemical characterization of amiodarone pigment.
• Findings suggest that amiodarone pigment is a metabolite of amiodarone, closely related to melanin.
• Understanding the nature of this pigment aids in diagnosing and managing amiodarone-related skin side effects.