So-called sclerosing hemangiomas of lung. An immunohistochemical study supporting a respiratory epithelial origin.

Sclerosing hemangiomas are benign pulmonary neoplasms. They were initially believed by Liebow and Hubbell to be of endothelial origin; however, subsequent ultrastructural studies have suggested an alveolar pneumocyte and mesothelial derivation. Using a panel of various antibodies on eight cases, the authors found that sclerosing hemangiomas expressed cytokeratin (seven cases), epithelial membrane antigen (seven cases), carcinoembryonic antigen (five cases), vimentin (seven cases), surfactant apoprotein (eight cases), and Clara cell antigen (five cases). These results support the hypothesis that sclerosing hemangiomas represent an epithelial tumor showing simultaneous bronchiolar epithelial and alveolar pneumocyte differentiation.