Amiodarone-induced thyrotoxicosis

Aims Amiodarone is an iodine-rich drug widely used for the management of various cardiac arrhythmias and severe congestive heart failure. Thyroid dysfunction is an important side-effect of amiodarone therapy. Amiodarone-induced thyrotoxicosis is a complex diagnostic and therapeutic challenge. It can occur in apparently normal thyroid glands and in glands with pre-existing abnormalities. The aim of this study was to investigate the histo-pathological and immunohistochemical features of a total thyroid-ectomy specimen in a 70-year-old man with amiodarone-induced thyrotoxicosis. Methods Paraffin embedded thyroid tissues were stained with haematoxylin and eosin and special immunohistochemical and histochemical stains. Results Histological examination revealed destruction of the thyroid follicles with areas of degeneration and involution of the follicles. Together with chronic inflammatory changes and fibrosis, foamy cells containing fine-brown pigments filled approximately 50% of the follicles. Discussion The histological features of our case were in keeping with amiodarone-induced thyrotoxicosis.