Inflammatory fibroid polyp mimicking an early gastric cancer

A 62-year-old man underwent EGD to follow up an antrum lesion, which had been first detected as a depressed lesion 5 years earlier (A). Examination of biopsy specimens of the lesion taken at annual intervals repeatedly resulted in inflamed gastric mucosa. However, the lesion had gradually increased in size from 10 mm to 18 mm, and the depressed area had also become more marked over the years (B). Magnifying endoscopy with narrow-band imaging revealed that the lesion had an irregular microvascular pattern within (C). Because the endoscopic findings were similar to those of early gastric cancer, we performed diagnostic endoscopic submucosal dissection (ESD). Histologically the lesion was composed of spindle cells and small vessel proliferation accompanied by eosinophil-rich inflammation. The spindle cells showed CD34 (+), CD117 (-), DOG-1 (-), desmin (-), and S100 (-) in immunohistochemistry. On the basis of these observations, the lesion was diagnosed as an inflammatory fibroid polyp (IFP) (D, H&E, orig. mag. ×400). IFPs are relatively rare lesions found in the GI tract, especially in the gastric antrum. Although IFPs typically present as submucosal tumors or polypoid lesions, they may present progressive depression mimicking early gastric cancer.