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.
Endothelium/ultrastructure ; Female ; Histiocytoma, Benign Fibrous/pathology/*ultrastructure ; Humans ; Lung Neoplasms/pathology/*ultrastructure ; Male ; Middle Aged

OBJECTIVETo study the clinicopathologic features, differential diagnosis and pathogenesis of sclerosing angiomatoid nodular transformation of spleen.

METHODSTen cases of sclerosing angiomatoid nodular transformation of spleen were retrieved from the archival file. Histochemical and immunohistochemical (EnVision method) studies were performed. Ultrastructural findings were also available in one of them.

RESULTSSclerosing angiomatoid nodular transformation was characterized by micronodular appearance of vascular spaces lined by plump endothelial cells with interspersed ovoid spindle cells. Immunohistochemical study showed that the endothelial cells of vessels in the angiomatoid nodules had various expressions of immunologic phenotypes and could be mainly classified into 3 types: CD34(+)/CD31(+)/CD8⁻ endothelial cells of the capillaries, CD8(+)/CD31(+)/CD34⁻ lining cells of the sinusoids and CD31(+)/CD8⁻/CD34⁻ endothelial cells of the small veins. Collagen network and dilated lymphatic sinuses were evident under transmission electron microscope.

CONCLUSIONSSclerosing angiomatoid nodular transformation of spleen is a rare benign entity. It may represent a reactive condition and bears some relationship with splenic angioma. It needs to be distinguished from borderline or malignant vascular tumors of spleen.

Adult ; Antigens, CD34 ; metabolism ; CD8 Antigens ; metabolism ; Diagnosis, Differential ; Female ; Hemangioendothelioma ; metabolism ; pathology ; Hemangiosarcoma ; metabolism ; pathology ; Histiocytoma, Benign Fibrous ; metabolism ; pathology ; surgery ; ultrastructure ; Humans ; Male ; Microscopy, Electron ; Middle Aged ; Platelet Endothelial Cell Adhesion Molecule-1 ; metabolism ; Splenic Neoplasms ; metabolism ; pathology ; surgery ; ultrastructure