A Rare Imposter of Acute Abdomen: Third-part Duodenal Diverticulum with Phytobezoar

Duodenal diverticula are usually asymptomatic, with only 1%–5% becoming clinically significant. Diverticula involving the third part of the duodenum (D3) are rare and may radiologically mimic perforation. We report a 70-year-old male presenting with diffuse abdominal pain, mild distension and constipation. Clinical examination revealed tachycardia without peritonitis. Contrast-enhanced computed tomography suggested a distal D3 perforation with retroperitoneal collection; however, clinicoradiological discordance prompted further evaluation. Push enteroscopy revealed a large D3 diverticulum containing a phytobezoar, which was removed endoscopically. The patient improved with conservative management. Careful clinical correlation and endoscopic evaluation can prevent unnecessary surgery in selected patients.