So-called sclerosing hemangioma of the lung--two cases report with ultrastructural study.

Sclerosing hemangiomas of the lung are benign neoplasms of uncertain histogenesis. We analysed two cases of sclerosing hemangiomas of the lung with histochemistry and electron microscopy. They had a variegated histologic appearance characterized by an admixture of solid, hemorrhagic, papillary and sclerotic lesions. Characteristic uniform round cells, unique to this tumor, were found within the stroma in all lesions. In the electron microscopic examination, we found Weibel-Palade bodies like small bodies in the tumor cells. We suspect hypothesis originating in the endothelial cell can not be completely excluded yet. Sclerosing hemangioma is a distinct clinicopathologic entity and should be distinguished from other benign neoplasms or inflammatory lesions of the lung.