Calcifying fibrous pseudotumor of mesentery presenting with acute peritonitis - Case report with immunohistochemical study and review of literature

Calcifying fibrous pseudotumor (CFP) is a benign soft tissue lesion compose d of thick collagen bundles, scattered fibroblasts, and psammomatous and dy strophic calcifications, located most commonly in the extremities and trunk of children and young adults. The present case in a 36-year-old woman is t o the best of our knowledge the first report of a large CFP confined to the mesentery, which, because of torsion, led to acute peritonitis and emergen cy laparotomy. The typical histologic features were accompanied by a promin ent myofibroblastic proliferation along with inflammatory response at the p eriphery of the lesion. The spindle cells of the lesion were positive for v imentin and focally for CD34 and smooth-muscle actin. Review of the literat ure and discussion of differential diagnosis in this report focuses on abdo minal CFP and other intraabdominal soft tissue lesions, some of which may b e precursors of CFP.