Abstract

H?rthle cell adenoma of the thyroid gland is a morphologically peculiar tumor. The tumor cells have numberous mitochondria and scanty cell organelles and show strong eosinophilicity on hematoxylin and eosin stain. A case of H?rthle cell adenoma of the thyroid gland was studied by light and electron microscopy. The most distinctive ultrastructural feature was also mitochondrial abundancy with occasional admixture of cystically dilated rough endoplasmic reticulums. The authors discussed the ultrastructure of H?rthle cell adenoma with a review of literatures.