Gastric volvulus associated with preduodenal portal vein in right isomerism: a case report.

Preduodenal portal vein (PDPV) is a rare vascular anomaly associated with heterotaxy syndrome, typically presenting as duodenal obstruction in left isomerism. We report a 13-month-old male with right isomerism, single ventricle physiology, and asplenia who presented with postprandial vomiting. Computed tomography revealed a PDPV anterior to the pylorus, and upper gastrointestinal contrast study confirmed mesentericoaxial gastric volvulus. Surgery consisted of gastric derotation, ante-PDPV pyloroduodenostomy, and anterior gastropexy. The patient recovered uneventfully and remained asymptomatic at 9-month follow-up. To our knowledge, this is the first report of PDPV with right isomerism complicated by gastric volvulus. Absent gastric stabilizing ligaments in asplenia, combined with PDPV-related obstruction, may predispose to volvulus. Multimodal imaging and individualized surgical management are essential in this rare setting.