Calcifying Fibrous Tumor of the Gastrointestinal Tract.

Calcifying fibrous tumor is a benign mass lesion classically described as a soft tissue tumor. However, a thorough review of the literature reveals that it can occur virtually anywhere, including the tubular gastrointestinal (GI) tract. Its clinical manifestations are variable in the GI tract, and its imaging findings are nonspecific. However, it has unique histologic and immunophenotypical features that must be recognized by GI pathologists to differentiate it from an assortment of other rare mesenchymal lesions of the abdomen and GI tract. Calcifying fibrous tumor is composed of a paucicellular collagen matrix, interspersed calcified bodies, and a sparse inflammatory infiltrate. Although calcifying fibrous tumor is benign, pathologists must be aware that it may occur in the GI tract to differentiate it from other potentially more aggressive, rare mesenchymal lesions.