Original ArticlesA Clinicopathologic Study of 100 Cases of Pulmonary Sclerosing Hemangioma With Immunohistochemical Studies TTF-1 Is Expressed in Both Round and Surface Cells, Suggesting an Origin From Primitive Respiratory EpitheliumDevouassoux–Shisheboran, Mojgan M.D.; Hayashi, Tomayoshi M.D.; Linnoila, R. Ilona M.D.; Koss, Michael N. M.D.; Travis, William D. M.D. Author Information From the Department of Pulmonary Pathology (M.D.-S., M.N.K., W.D.T.), Armed Forces Institute of Pathology, Washington, DC; the Department of Pathology (M.D.-S.), Hospices Civils de Lyon, Hôpital de la Croix Rousse, Lyon, France; the Department of Pathology (T.H.), Nagasaki University Hospital, Japan; and the Cell and Cancer Biology Department (R.I.L.), Medicine Branch, National Cancer Institute, National Institutes of Health, Rockville, Maryland, U.S.A. Address correspondence and reprint requests to William D. Travis, MD, Department of Pulmonary and Mediastinal Pathology, Building 54, Room M003B, Armed Forces Institute of Pathology, 6825 NW 16th Street, Washington, DC 20306-6000, U.S.A.; e-mail: [email protected] The American Journal of Surgical Pathology: July 2000 - Volume 24 - Issue 7 - p 906-916 Buy Abstract Pulmonary sclerosing hemangioma (SH) is a lung neoplasm of uncertain histogenesis that is composed of two major cell types: surface and round cells. The authors studied 100 cases of pulmonary SH that presented as a peripheral (95%), solitary (96%) mass of less than 3 cm in diameter (74%) in asymptomatic patients who were mostly women (83%) with a mean age of 46.2 years. Immunohistochemistry of multiple epithelial, mesothelial, pneumocyte, neuroendocrine, and mesenchymal markers was performed on 47 cases to investigate the histogenesis of this neoplasm. Both surface and round cells stained with epithelial membrane antigen (EMA) and thyroid transcription factor-1 (TTF-1) in more than 90% of cases; however, the round cells were uniformly negative for pancytokeratin and positive for cytokeratin-7 and CAM5.2 in only 31% and 17% of cases, respectively. Surfactant proteins A and B as well as Clara cell antigen were positive in varying numbers of surface cells but they were negative in the round cells. Neuroendocrine cells either as isolated scattered cells or as a tumorlet within the center of SH were detected (chromogranin, Leu-7, synaptophysin positive) in three cases. The expression of TTF-1 in the absence of surfactant proteins A and B and Clara cell antigens in the round cells of SH suggests that they are derived from primitive respiratory epithelium. The alveolar pneumocytes and neuroendocrine cells may either represent phenotypic differentiation of a primitive respiratory epithelial component or they may correspond to non-neoplastic entrapped or hyperplastic elements. The concomitant positivity of both cell types in SH for TTF-1 and EMA, and the negativity of round cells for pancytokeratin and neuroendocrine markers, provide useful clues not only for histogenesis but also for the diagnosis of this lung neoplasm. © 2000 Lippincott Williams & Wilkins, Inc.