# Navigating the Labyrinth: When the “Mesenterium Commune” Turns Colonoscopy into an Endoscopic Rollercoaster

## TL;DR

A rare anatomical condition called 'Mesenterium commune' caused a difficult colonoscopy in a woman with recurring abdominal pain and a history of celiac disease.

## Contribution

This case highlights the diagnostic challenges and clinical implications of the rare 'Mesenterium commune' condition.

## Key findings

- The patient's colon was abnormally located on the left side of the abdomen due to 'Mesenterium commune'.
- Virtual colonoscopy was necessary to complete the examination due to the anatomical variant.
- Mesenterium commune is a rare developmental anomaly that can cause chronic abdominal symptoms and intestinal obstruction.

## Abstract

These images involved the case of a 51-year-old woman who had a history of chronic abdominal pain, iron deficiency, and diarrhoea but no blood or mucus in her stool. She had never undergone major abdominal surgery, and her past medical evaluation diagnosed her with celiac disease, leading to the adoption of a gluten-free diet alleviating most of her gastrointestinal symptoms. However, years later, her abdominal pain returned, so she underwent an abdominal ultrasound, revealing non-specific bowel loop dilation, and a weakly positive faecal occult blood test led to a colonoscopy. Despite many efforts to advance the scope beyond the transverse colon, colonoscopy was arduous and not complete, even after several changes in decubitus and abdominal compressions. Therefore, a virtual colonoscopy was conducted, revealing no intraluminal masses, but the entire colon was located on the left side of the abdomen. Indeed, the results showed sigma and that most of the colon was curled up in the small pelvis. This rare anatomical variant, known as “Mesenterium commune” (MC), is a type of gut malrotation that develops in childhood due to a lack of omphalomesenteric loop rotation during the embryonic period. This condition can lead to episodes of intestinal obstruction, potentially resulting in an acute abdomen and leading to surgical correction. Symptoms include chronic recurring abdominal pain, nausea, vomiting, and occasionally bloody stools. Few cases of this extremely rare condition have been reported in the literature so far.