Sclerosing angiomatoid nodular transformation of the spleen.

OBJECTIVE To study clinical and pathologic features of sclerosing angiomatoid nodular transformation (SANT) and differential diagnosis, we reviewed splenectomy specimens from the Department of Pathology, First Affiliated Hospital, School of Medicine, Zhejiang University (January 1990 to December 2006) and another case from consultation at Second Jiaxing Municipal Hospital, Zhejiang Province, finding 7 cases of this lesion. STUDY DESIGN Clinicopathologic characteristics and immunophenotype of 7 cases of SANT were studied. RESULTS Five cases were incidentally found during routine examination. One had concurrent hepatic angioma. Microscopically, all cases were characterized by multiple angiomatoid nodules of various sizes embedded in fibrosclerotic stroma. Each nodule was composed of slit-like, round or irregularly shaped vascular spaces lined by plump endothelial cells and interspersed by a population of spindle or ovoid cells. In one case, an angiomatoid nodular lesion and a hamartoma-like lesion appeared together. Heterogeneous immunohistochemical features of the lining cells were revealed. CD34 was expressed in the narrow, well-formed capillaries and CD8 in some sinusoid-like structures, but without CD34 expression. CD31 staining highlighted numerous lining cells and interspersed cells. Some lining cells were focally CD68 positive. CONCLUSION SANT is a rare lesion. Based on morphologic and immunohistochemical features, it may be a variant of splenic hamartoma.