Vascular lesions in the biopsied bronchus of patients with sarcoidosis changes of the endothelial cells in aggregation of eosinophils.

1) Aggregates of eosinophils closely related to the enlarged endothelial cells in the capillary vessels were recognized in 64% of 28 cases in biopsied specimens of the major bronchus of patients with sarcoidosis. 2) Electron microscopy revealed the vacuolated central cores or matrix in the specific granules of the eosinophils adjacent to the swollen vascular endothelial cells, frequent findings with attachment of the blood platelets to the damaged plasma membrane of the endothelial cells eventually becoming occluded in the lumen with platelet thrombosis, and multilayer formation of the basement membrane of the capillary vessels. 3) Sarcoidosis is suggested to be a pathological process producing both granuloma formation in each organ and vascular endothelial cell changes in the capillary vessels accompanied by aggregation of eosinophils in some periods of the disease process due to unidentified etiological factors.