INCIDENTAL PREDUODENAL PORTAL VEIN CAUSING PARTIAL DUODENAL OBSTRUCITON AND HYPERTROPHIED PRE-PYLORIC GASTRIC POLYP

Objectives: Preduodenal portal vein (PDPV) is a rare congenital anomaly in which the portal vein lies anterior to the duodenum rather than its normal posterior position. PDPV is a known rare cause of duodenal obstruction, typically of the second portion, and can be associated with other anomalies such as malrotation with or without jejunal atresia. Here we report a case of presumed partial gastric outlet obstruction wherein the authors discovered a partial first portion of the duodenum obstruction due to a PDPV. A female patient, born at 28+4 weeks of gestation via cesarean section, was admitted to the neonatal intensive care unit with bronchopulmonary dysplasia, and was referred to the surgical service for percutaneous endoscopic gastrostomy tube placement in conjunction with the gastroenterology service due to failed modified barium swallow study with significant aspiration risk. During this procedure, a partially obstructing 1.5-cm pre-pyloric polyp was encountered, deemed not amenable to endoscopic resection, and the procedure was aborted. A laparotomy with transverse supraumbilical incision was then performed with the intention of polyp resection and open gastrotomy tube placement. During initial exploration, a preduodenal portal vein was readily identified that appeared to be partially obstructing the first portion of the duodenum, creating an effective gastric outlet obstruction. The anterior gastrotomy was made and the large polyp was excised and sent for pathology; it appeared benign in nature. A diamond-shaped duodenoduodenotostomy was then created anterior to the portal vein, which was left in situ. A Stamm gastrostomy was created, and the procedure concluded. Pathologic evaluation of the pre-pyloric polyp revealed a hyperplastic polyp without dysplasia or malignancy. The patient’s anastomosis was assessed with an Upper GI series on postoperative day 5, showing no evidence of a leak. By postoperative day 29, the patient was able to be discharged home and was tolerating gastrotomy tube feeds at goal. At follow-up, the patient is still gastrotomy tube dependent due to oropharyngeal dysphagia but tolerates them well with her most recent BMI in the 93rd percentile. PDPV is a rare congenital anomaly. The suggested approach is to leave the PDPV in situ and create a diamond-shaped duodenoduodenostomy to alleviate the obstructive nature of the PDPV. This was performed in our case and the patient had an acceptable clinical course. To our knowledge, this is the first report in the literature of a hypertrophied antral polyp associated with a PDPV.

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