Duodenum inversum presenting with intestinal obstruction in a 40-day-old infant: a case report

Background Duodenum inversum is a rare congenital anomaly characterized by an abnormal course of the duodenum with preservation of a normally positioned duodenojejunal junction. Clinical presentation is highly variable, ranging from incidental findings to symptoms of upper gastrointestinal obstruction. Due to its rarity, diagnosis and management remain challenging, particularly in pediatric patients. Case presentation We report the case of a 40-day-old female infant presenting with recurrent postprandial vomiting and poor weight gain since the first days of life. Initial clinical, metabolic, and ultrasonographic evaluations were unremarkable, including exclusion of hypertrophic pyloric stenosis. A trial of conservative management provided only temporary improvement. A subsequent upper gastrointestinal contrast study suggested an abnormal duodenal configuration, while endoscopic and radiological reassessment demonstrated a reversed and tortuous duodenal course consistent with duodenum inversum. Following recurrence of symptoms and failure of conservative measures, the patient underwent exploratory laparotomy, which revealed a mobile duodenum with fibrotic adhesions between the duodenum, colon, and retroperitoneum causing functional obstruction. Adhesiolysis restored normal duodenal anatomy. The postoperative course was uneventful, with complete resolution of symptoms and appropriate growth at 6-month follow-up. Conclusion Although duodenum inversum is typically asymptomatic, it may rarely present in infancy with significant obstructive symptoms. Fibrotic adhesions are thought to contribute to the pathophysiology of obstruction in symptomatic cases, although their precise role remains incompletely understood. Upper gastrointestinal contrast studies remain the main diagnostic tool, while surgical treatment is reserved for patients with persistent or complicated obstruction. Awareness of this entity is essential to avoid misdiagnosis and to ensure appropriate management. To our knowledge, our case represents the youngest patient requiring surgery reported in the literature.