Immunohistochemical Study of So-called Sclerosing Hemangioma of the Lung

Abstract

The origin of tumor cells composing sclerosing hemangioma of the lung has been extensively studied by many researchers, but it is still obscure. We analyzed seven cases of sclerosing hemangioma of the lung from the files of Seoul National University Hospital, Department of Pathology by immunohistochemical staining as well as histologic observation. The tumors are composed of two kinds of cells; the epithelial cells lining the papillary area are cytokeratin( +) and vimentinl -), while subepithelial tumor cells are cytokeratin( -) and vimentinl +). Two kinds of cells are separated by basement membrane, visualized by type IV collagen monoclonal antibody. The angiomatous and solid areas are devoid of cytokeratin( +) epithelial cells and basement membrane is not formed beneath the blood-filled cysts. The epitheial cells are frequently seen at the periphery of the tumor, where the epithelial cells maintain their pseudostratified and ciliated character of bronchiolar lining epithelium. The above findings suggest that the epithelial cells would not be tumor cells but an entrapped mucosa, and that the tumor cells be not of epithelial origin.