Median Arcuate Ligament Syndrome Without Static Image Findings of Celiac Artery Compression: The Potential Existence of a Pure Neurogenic Subtype

Symptomatic median arcuate ligament syndrome (MALS) is considered to be a diagnosis of exclusion, and there is no consensus about its diagnostic criteria. We present the case of a 39-year-old woman, who presented with persistent epigastric pain. A computed tomography scan did not show external celiac artery (CA) stenosis. Ultrasonography showed that the peak systolic blood flow velocity of the CA in inspiration and expiration position was 1.13 m/sec and 2.16 m/sec, respectively. The difference in the angle between the aorta and CA between maximum inspiration and maximum expiration was >50°. Only the patient's physical findings were suggestive of MALS, as the ultrasonographic findings demonstrated normal flow without compression through the celiac axis. The patient underwent laparoscopic division of the median arcuate ligament (MAL), and her symptoms disappeared postoperatively. The pathophysiology of MALS remains unclear, and our case suggests the potential existence of a neurogenic subtype in which MAL compresses the celiac plexus, but not the CA.