An unusual developmental anomaly of duplicated portal vein.

BACKGROUND: Portal vein (PV) duplication is a rare developmental anomaly but has an important role in the diagnosis and management of disease for radiologists and surgeons.

MATERIALS AND METHODS: A new variant of PV duplication with vein fenestration leading to choledochal stenosis and dilatation and thrombus was identified by computed tomography angiography (CTA) on a 59-year-old woman with a history of gallstones.

RESULTS: A second PV originated from the superior mesenteric vein (SMV), split into two branches that encircling the common bile duct to form a vein fenestration, leading to choledochal stenosis and dilatation, with thrombus formation at the confluence.

CONCLUSIONS: This case report adds to the existing body of knowledge about the variation of the PV system. We present an embryological perspective for the case, which suggests the possibility of similar occurrences.