Unusual phenomenon-"polyp" arising from a diverticulum: A case report

BACKGROUND Sealed perforation of colonic diverticulum is a common clinical condition and may be differentiated from an underlying malignant perforation using interval endoscopy. We present an uncommon colonoscopy finding of a healed diverticular perforation, mimicking a polyp, 6 wk post-diverticulitis-something that has not been reported in literature. We aim to shed light on the likely process that resulted in the trompe l'oeil after diverticulitis. This also introduces the possibility of more targeted colonic resection in the event of a similar recurrence. CASE SUMMARY A middle-aged Chinese female presented with a 3-d history of non-colicky left iliac fossa pain. It was associated with fever (T-max 37.6 degrees C), non- bloody diarrhoea and non-bloody, non- bilious vomiting. She had a history of Type 2 diabetes mellitus, well controlled on metformin. Tenderness was noted on the left iliac fossa region with no guarding or mass. Total white cell count (11.45 x 109/L) and C-reactive protein levels (213.9 mg/L) were elevated. Computed tomography imaging of the abdomen revealed pericolonic fat stranding and extraluminal air pockets fluid density with peritoneal thickening at the sigmoid colon, likely representing a sealed perforation. Six weeks after the episode, she underwent a follow-up colonoscopy. An exophytic polypoid lesion closely associated with a diverticulum was seen in the sigmoid colon. The lesion was easily "pinched" off without much effort using endoscopic forceps and sent for histology which revealed granulation tissue suggesting a healed diverticular perforation. CONCLUSION Granulation tissue associated with healed diverticular perforations resemble polyps. Tattooing around these sites may allow for future targeted colonic resections.