Calcifying fibrous pseudotumor of mediastinum--a case report.

This report presents a case of calcifying fibrous pseudotumor arising in the posterior mediastinum of a 54-year-old woman. The histopathologic features of this case were identical to that of calcifying fibrous pseudotumor first designated in 1993. It is a distinctive benign fibrous lesion characterized by the presence of characteristics psammomatous or dystrophic calcification, abundant hyalinized collagen and lymphoplasmacytic cell infiltrate. Immunohistochemically most of the scattered fibroblasts were positive for vimentin, but not for CD-34 and cytokeratins, distinguishing it from solitary fibrous tumor of pleura and desmoplastic mesothelioma. The unusual site of the posterior mediastinum and the old age characterize this case.