Inflammatory myoglandular colonic polyp with adenomatous changes mimicking malignant tumor

Abstract

Inflammatory Myoglandular polyps (IMGPs) are rare intestinal polyps that occur frequently in the left colon and may present with hematochezia. Only a small number of cases have been reported in the right colon (2%). We present a case of IMGP in the proximal ascending colon. A 46-year-old woman of mixed ethnicity presented with a history of abdomino-pelvic pain and constipation. CT scan suggested possibility of malignancy. On colonoscopy, a non- obstructive polyp in proximal ascending colon was biopsied followed by right hemicolectomy. Patient also underwent total abdominal hysterectomy at the same time for fibroids. The colonic polyp revealed features of IMGP with focal adenomatous changes. The polyp was characterized by epithelial erosion, inflamed granulation tissue, hyperplastic and dilated glands, and proliferating smooth muscle. IMGP needs to be distinguished from other non-neoplastic colonic polyps, which includes Peutz-Jeghers polyps, inflammatory pseudopolyps, juvenile polyps, and inflammatory fibroid polyps. We report a large sized inflammatory myoglandular polyp with suspicious imaging findings and presence of adenomatous changes that mimicked malignancy that requires comprehensive evaluation and follow up.