Intramitochondrial crystalline inclusions in the liver of a patient with hyperthyroidism

The case of a female patient with hyperthyroidism and slightly impaired liver function is described. Histological examination of liver biopsy did not reveal any pathological findings. Electron microscopic examination revealed crystalline inclusions in a great number of the mitochondria of the liver cells, as well as increased size of the mitochondira. Similar findings were obtained upon examination of a liver biopsy performed six months after start of treatment for hyperthyroidism. Examination of the skin, muscle and white blood cells did not show the presence of such inclusions in the mitochondria. The significance of these findings in the liver cells is discussed.