Aurora rings may not always indicate an inverted colonic diverticulum: Report of a rare case of colonic lipoma

Aurora rings are prominent endoscopic features of the inverted colonic diverticulum (ICD), and their appearance alongside a colonic lipoma is an unprecedented phenomenon. The present study reports a case of colonic lipoma with Aurora rings, contradicting the assumption that Aurora rings are indicative of ICD. A 52‑year‑old male patient presented with left‑sided abdominal pain for >1 year, associated with constipation in the form of the decreased frequency of bowel motions every 4 to 5 days. A physical examination revealed an obese, protuberant abdomen and a mildly tender left iliac fossa region without other notable findings. A transabdominal ultrasonography revealed a thickening of the large bowel wall (<7 mm) with a suspected inflammatory lesion on the left side of the colon. During an ileocolonoscopy, multiple diffuse diverticula of various sizes were observed, affecting the entire colonic mucosa. Furthermore, a large (1.5 cm) pedunculated polyp with a thick stalk was found in the sigmoid colon, exhibiting positive Aurora rings. A polypectomy was conducted with the deployment of two hemoclips at the polyp base to prevent perforation. The histopathological examination of the specimen, a 1.3 cm polyp, revealed the presence of a colonic lipoma, rather than an ICD. The identification of Aurora rings has emerged as a significant endoscopic feature in the diagnosis of ICD; nevertheless, the underlying etiology of these rings remains elusive. Based on an extensive search of the literature, no study was found mentioning the appearance of Aurora rings in an endoscopic screening of other colonic conditions other than ICD. The appearance of Aurora rings alongside a colonic lipoma has not previously been mentioned, at least to the best of our knowledge, which renders the differentiation of ICD from lipomas and polyps more challenging.