Imaging findings and clinical features of atypical retroperitoneal abscess caused by duodenal perforation: a case report and review of the literature.

A retroperitoneal abscess caused by duodenal perforation is a relatively rare disease clinically. We report the case of a patient with a local high-density shadow at the head of the retroperitoneal pancreas. A 28-year-old Chinese man presented with fever and abdominal pain after overeating and heavy drinking. On physical examination, he had mild tenderness in his upper abdomen. Laboratory examination results showed a white blood cell count of 24.06 109/L and a neutrophil absolute value of 18.81 109/L, and a computed tomography scan showed an irregular soft tissue mass with uneven enhancement of the cystic wall in the retroperitoneal space. Gastroscopy showed that there was a fistula in the anterior wall of the duodenal bulb. Endoscopic anastomosis clip system (over-the-scope clip) of the duodenal fistula was performed successfully. After the operation, nasal feeding was provided with a nutrition tube, and empiric anti-infection, acid-inhibiting, and stomach-protecting treatments were administered. Our patient’s body temperature gradually returned to normal, and his abdominal pain decreased. A retroperitoneal abscess caused by duodenal perforation can be diagnosed by clinical symptoms and abdominal computed tomography imaging. The choice of treatment should be based on accurate and timely clinical and imaging data.