Dunbar syndrome, also known as median arcuate ligament syndrome (MALS), is a rare condition affecting approximately 2 per 100,000 individuals. It is most often diagnosed between 20 and 50 years of age, with a female-to-male ratio of 4 : 1. In this disorder, the celiac trunk is compressed by the median arcuate ligament (MAL). Typical symptoms include postprandial or exercise-induced epigastric pain, weight loss, nausea, and vomiting [1].

The MAL connects the crura of the diaphragm as they pass over the aorta, typically above the origin of the celiac trunk. However, in 10–24% of individuals the ligament runs lower and crosses the proximal segment of the celiac trunk [2]. The development of collateral circulation, primarily around the pancreas, plays a key role in symptom manifestation and significantly increases the risk of aneurysm formation in visceral vessels [3].

We report the case of a 19-year-old male with a history of Crohn’s disease (CD) diagnosed at the age of 8 years, who had been receiving upadacitinib since July 2024 with good clinical response and tolerance. The patient was admitted to the Gastroenterology Clinic with symptoms suggestive of disease exacerbation, including worsening abdominal pain, low-grade fever, unintentional weight loss (11 kg over 3 months), and nausea. The patient noted that, unlike his previous episodes of pain localised in the lower abdomen, the current pain was epigastric and correlated with meal volume.

Laboratory tests revealed elevated inflammatory markers (C-reactive protein [CRP], 86.3 mg/l; reference range < 5 mg/l). Computed tomography (CT) angiography was performed and compared with a scan obtained 6 months earlier. Inflammatory changes in the terminal ileum, ascending colon, and transverse colon had regressed. However, the new study revealed a 6-mm segment of the celiac trunk without contrast enhancement, caused by external compression and the presence of collateral circulation within the pancreatic head (Figures 1 A, B). The previous CT scan had shown only moderate celiac trunk stenosis with collateral circulation.

A laparotomy was performed, during which the MAL fibres were divided. Postoperatively, the patient’s pain improved, and CRP levels decreased. One month later, during follow-up, the pain recurred, accompanied by signs of CD exacerbation. Laboratory tests again revealed elevated CRP levels (80.9 mg/l). Repeat CT angiography demonstrated progression of...


View full text