The tunica propria in rhinoscleroma. An electron microscopic study.

The ultrastructure in 15 cases of scleroma was studied. The vacuoles of the Mikulicz cells had a definite limiting membrane containing two types of granular material, "A" considered to be antibody, and "B" considered antigenic. Inside the vacuoles infrequent beaded filamentous crystalloid structures were seen, probably of a proteinaceous nature. An enzymatic etiology causing disruption of the limiting vacuolar membrane was considered. New ultrastructural characteristics of the 'early' Mikulicz cell are described. The capillaries occasionally showed subendothelial amyloid deposition. The seromucinous glands were infrequent but of normal character.