Chronic diarrhea as an atypical presentation of complete common mesentery in an adult: A case report

Complete common mesentery (CCM) is a rare congenital anomaly of intestinal rotation, typically discovered incidentally or during acute abdominal events. Chronic gastrointestinal symptoms, such as persistent diarrhea, have not been previously described as a presenting sign. We report the case of a 56-years-old female with chronic diarrhea and mild abdominal discomfort. Imaging revealed a complete common mesentery. The patient was managed conservatively with symptom improvement. CCM is usually asymptomatic or presents with acute complications such as volvulus or left-sided appendicitis. This case highlights the possibility of chronic functional gastrointestinal manifestations due to congenital anatomical anomalies. We discuss the embryological background, diagnostic imaging, clinical presentations, and therapeutic considerations. In cases of unexplained chronic diarrhea, clinicians should consider rare anatomical variants like CCM, particularly when standard diagnostic approaches are unrevealing.