The ultrastructure of cholesterol granuloma of the middle ear: an electron microscope study.

The ultrastructure of giant cells in cholesterol granuloma is described, with particular reference to their role in the absorption of cholesterol needles. Cholesterol is a highly resistant substance in its crystalline form and it is confirmed that the giant cells are endowed with endoplasmic structures and organelles and are partly crowded with lysosomes, as evidence of the active role of the giant cells in the absorption and removal of cholesterol formed in the granuloma from blood, mucus or necrotic material.