Dunbar syndrome, also known as Median Arcuate Ligament Syndrome (MALS), is a vascular compression disorder resulting from the external compression of the celiac artery by the median arcuate ligament of the diaphragm. This anomaly leads to postprandial abdominal pain, nausea, and weight loss due to impaired blood flow or celiac plexus irritation. While often incidental, clinical significance arises when patients present with chronic, unexplained abdominal symptoms. We report a case of Dunbar syndrome identified on CT angiography in a symptomatic middle-aged woman, emphasizing the role of cross-sectional imaging in diagnosis.
A 34-year-old female presented with intermittent upper abdominal pain, particularly in the epigastric region. The pain was non-radiating, worsened post prandial, and was occasionally associated with nausea. She had a previous history of gallbladder polyps, though no polyp was detected on current imaging. There was no history of prior abdominal surgeries or similar past episodes.
To evaluate for vascular or structural causes, a contrast-enhanced CT abdomen with angiographic protocol was performed.
CT angiography of the abdomen revealed the following: – Focal, high-grade narrowing at 4 mm from origin of the celiac artery, with a characteristic “hooked” appearance on sagittal reformats. – Post-stenotic dilatation of the celiac trunk was noted.
Chronic postprandial abdominal pain mimicking peptic or hepatobiliary disease. – Delayed diagnosis due to nonspecific gastrointestinal symptoms. – Importance of dynamic imaging (inspiration and expiration) in evaluating vascular compression. – Surgical relevance in planning laparoscopic release of the median arcuate ligament. – Risk of misdiagnosis as functional gastrointestinal disorder or psychosomatic symptoms.
Dunbar syndrome arises due to the anatomical variation where the median arcuate ligament lies lower than usual, compressing the celiac trunk. It is more prevalent in young to middle-aged females. The compression may lead to ischemic symptoms or stimulation of the celiac ganglia, producing pain.
CT angiography is the diagnostic modality of choice, providing detailed evaluation of arterial anatomy and dynamic changes. The classic hooked contour of the celiac artery on sagittal view and post-stenotic dilatation are diagnostic hallmarks.
Chronic stenosis can cause increased collateral circulation, particularly through pancreaticoduodenal arcade and inferior mesenteric artery. The elevated flow and pressure within these vessels may predispose to formation of flow related aneurysms, particularly in pancreaticoduodenal or gastroduodenal arteries. These aneurysms have high risk of rupture.
Differentiation from atherosclerotic stenosis is essential, as the treatment differs significantly—surgical ligament release vs medical management. In symptomatic patients, laparoscopic MAL release significantly improves quality of life.
Dunbar syndrome is a rare yet important cause of chronic abdominal pain. Cross-sectional imaging, especially CT angiography, plays a pivotal role in identifying this condition. Early diagnosis enables timely surgical intervention, avoiding prolonged morbidity in these patients. This case highlights the importance of recognizing vascular compression syndromes as a differential in unexplained abdominal pain.
Dr. Akash Kumar B Y Associate consultant, Department of Radiology, Kauvery Hospital Chennai
Dr Manish Yadav DNB Radiology Resident, Kauvery Hospital Chennai
Dr Malavika S 1st Year PG DNB Radiology, Kauvery Hospital Chennai
Dr Kanagasabai Kamalasekar Consultant Radiology, Kauvery Hospital Chennai
