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.