Chalazion is a sterile foreign body granulomatous reaction to the lipid material of the meibomian glands of the tarsus or the glands of Zeiss. The gland's duct becomes blocked and the products spill over and the immune system recognizes it as a foreign body, resulting in inflammation , including epitheloid cells and multinucleated giant cells. In H and E preparations the fat is dissolved out, leaving clear areas. Lymphocytes, polymorphonuclear cells, epitheloid cells as well as giant cells may be present. Back to Eyelid