Duodenal diverticulum perforation with pneumo-retroperitoneum: a case report of rare presentation

Perforation of a duodenal diverticulum is rare but associated with high morbidity and mortality. Retroperitoneal perforations often present atypically, delaying diagnosis and management. We describe a 48-year-old woman presented to the hospital with abdominal pain after influenza A infection. Initial computed tomography suggested hollow viscus perforation, and she underwent laparoscopic lavage and drainage. Persistent bilious drainage and follow-up imaging revealed perforation of the third portion of the duodenum with retroperitoneal abscess. Exploratory laparotomy demonstrated a 2 × 2 cm perforated diverticulum at the inferior duodenal angle with surrounding necrosis. Segmental duodenectomy with duodenojejunostomy and feeding jejunostomy was performed. This case highlights the diagnostic difficulty of retroperitoneal duodenal diverticulum perforation and the importance of recognizing bilious drainage as an early warning sign. Conservative measures may be attempted in stable patients, but suspicion of ongoing leakage warrants timely definitive surgery. Early and comprehensive exploration may prevent delayed recognition and reduce morbidity.