A calcifying fibrous tumor of the stomach difficult to distinguish from gastrointestinal stromal tumor by preoperative endoscopic ultrasonography with a review of the literature

We report here a rare case of calcifying fibrous tumor of the stomach. A 35-year-old man had a medical checkup, where upper gastrointestinal endoscopy revealed a protruding submucosal tumor on the anterior wall of the gastric body with a slightly mild erythematous surface. Endoscopic ultrasonography showed a heterogeneous hypoechoic lesion with shadowing, consistent with calcification. Continuity between the tumor and the muscularis propria was suspected. Contrast-enhanced computed tomography showed a gastric tumor with delayed enhancement. Laparoscopic partial gastrectomy was performed. Microscopically, the tumor consisted of spindle-shaped cells with hyalinized fibrocollagenous tissue accompanied by psammomatous calcification and multifocal lymphoplasmacytic infiltrate. Immunohistochemically, the tumor was focally positive for CD34 and negative for c-kit, α-smooth muscle actin, desmin, S-100, and anaplastic lymphoma kinase. The tumor was diagnosed as calcifying fibrous tumor (CFT). CFT is a benign mesenchymal tumor, which is mainly found in soft tissues, and is rare in the stomach.