S3849 Not All Polyps Are Neoplastic: A Rare Case of Right-Colon IMGP

Introduction: Inflammatory myoglandular polyp (IMGP) is a rare, benign, non-neoplastic colorectal lesion characterized histologically by glandular distortion, proliferation of smooth muscle, and chronic inflammation within the lamina propria. First described in 1992, IMGPs are most commonly found in the left colon and rectum, with only a small number of cases reported in the proximal colon. Due to their rarity and nonspecific endoscopic appearance, they can be mistaken for adenomatous or neoplastic polyps, potentially leading to unnecessary interventions. We report a case of IMGP found in the ascending colon. Case Description/Methods: A 70-year-old man with prior medical history significant for hyperlipidemia and a remote history of a colonic polyp underwent a routine surveillance colonoscopy. During the procedure, a solitary 6 mm pedunculated polyp was identified in the ascending colon. The lesion was resected using a hot snare and retrieved intact. Histopathologic evaluation revealed features consistent with an inflammatory myoglandular polyp, including smooth muscle proliferation, and hyperplastic glands. No dysplasia or malignancy was noted. Discussion: This case highlights an unusual presentation of IMGP in the right colon and underscores the importance of histopathologic evaluation of colonic polyps. IMGPs are believed to arise from chronic mucosal trauma or prolapse, leading to smooth muscle and glandular proliferation with inflammation. Although often asymptomatic and discovered incidentally, they can present with rectal bleeding, anemia, or altered bowel habits. Recognizing this benign entity is essential to prevent misdiagnosis and unnecessary treatment. Clinicians should consider IMGP in the differential diagnosis of small, non-neoplastic polyps, particularly in atypical locations.