A 63-year-old patient was admitted to the hospital with a clinical picture of mechanical jaundice. A cystic tumor of the pancreas with invasion of the superior mesenteric, splenic veins, and common bile duct was detected. When visualizing the tumor, a 10 cm cyst was thinned out. Cholecystostomy was performed, after which the patient was referred for consultation and examination to the oncology center. At this institution, endoscopy and puncture of the cystic formation were performed. Pus (3 ml) containing Klebsiella was obtained, no cancer cells were found. In addition, stenosis of the postbulbar part of the duodenum was detected. The tumor is considered inoperable. The patient returned to us with a recommendation to impose a bypass biliodigestive anastomosis. We performed an ultrasound of the abdominal cavity - the cyst was no longer visualized, X-ray examination revealed leakage of contrast into the cyst cavity from the duodenum. We decided that the cyst was draining into the duodenum. The patient was operated on, choledochojejunostomy and gastrojejunostomy were performed on the Roux-en-Y loop. After the operation, the patient was hemodynamically unstable for 5 days and required inotropic support with norepinephrine, creatinine increased to 400 μmol / l, hypocoagulation was noted (INR before surgery 1.7, after 4.0), an increase in leukocytes to 30,000 and a left shift were noted. Amikacin was prescribed (in accordance with the sensitivity of Klebsiella) and sepsis symptoms began to subside. But from the 2nd day after the operation and up to today (10th day) up to 1.5 liters of serous fluid (without bile or intestinal contents) is released from the abdominal cavity through the drainage without a tendency to decrease. An increased number of leukocytes was revealed during the analysis of the fluid. The patient eats freely, does not have a fever and the problem of ascites has come to the fore. There was no ascites before the operation. Help with advice.