Electron microscopic demonstration of lysosomal inclusion bodies in lung, liver, lymph nodes, and blood leukocytes of patients with amiodarone pulmonary toxicity.

The mechanism of amiodarone-induced pulmonary toxicity is unknown. Two cases of amiodarone pulmonary toxicity are presented in which abnormal inclusion bodies containing whorls of membrane were seen on electron microscopy of extrapulmonary tissues. These cytoplasmic lysosomal inclusion bodies were observed in lymphocytes, plasma cells, granulocytes, tissue macrophages, and hepatocytes. These widespread histopathologic changes in extrapulmonary tissues and in a variety of cell types are similar to more extensively investigated findings in animal models that are thought to represent a drug-induced lysosomal storage disease, phospholipidosis.