A 56-year-old male patient with a history of positive serology for HIV and Hepatitis B presented with acute cholecystitis for which he underwent emergency laparoscopic cholecystectomy.

During the late postoperative period, one month after surgery, the patient presented a bilioma which was percutaneously evacuated. A biliary bypass is also performed by means of endoscopic cholangiography.

As a result of the above, the patient presented with acute pancreatitis associated with a peri-pancreatic collection. This collection was evacuated by means of an initial percutaneous drainage, which proved to be insufficient and the patient presented with a large retroperitoneal collection. With no improvement, and with persistent drainage debit associated with fever and deterioration of general condition, a CT scan of the abdomen and pelvis was performed. This showed encapsulated fluid with a hydro-aerial level in the right flank adjacent to the abdominal wall, extending 17 cm in the cranial-caudal direction and 11 x 3 cm in transverse diameter.

With a diagnosis of extraperitoneal right parietocolic abscess, drainage was performed by lumboscopy, evacuating abundant necrotic and purulent material.

Two pure silicone drains were placed opposite each other, creating a continuous lavage system, using slow-drip physiological solution.

The patient evolved favourably with few febrile registers. He had a positive culture for Pseudomona aureaginosa, which was treated with Meropenem during hospitalisation. On the fourth postoperative day, continuous lavage was replaced by a haemosuctor system and he was discharged.

During follow-ups, the patient remained afebrile and the drain was removed after cessation of drainage.