Duodenal perforation after retroperitoneal laparoscopic radical nephrectomy for ruptured malignant renal PEComa with spontaneous retroperitoneal hemorrhage: a case report.

Background: Perirenal perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm that can cause spontaneous retroperitoneal hemorrhage. Duodenal perforation after nephrectomy is rare but potentially life-threatening. Case presentation: We report a 52-year-old man with a right renal mass and spontaneous retroperitoneal hematoma who underwent retroperitoneal laparoscopic radical nephrectomy. Intraoperatively, a large, organized hematoma and dense adhesions were found between the renal upper pole and the second portion of the duodenum. Shortly after surgery, he developed acute abdominal pain with peritoneal signs, marked leukocytosis, rapidly elevated procalcitonin, and markedly elevated urine amylase (hyperamylasuria). Emergency laparotomy revealed a small duodenal perforation, which was treated with debridement, primary repair with omental reinforcement, drainage, and jejunal feeding tube placement. He recovered gradually​ and was discharged on postoperative day 17. Pathology confirmed malignant perirenal PEComa with extensive intratumoral hemorrhage, capsular rupture, and a high Ki-67 index; follow-up CT at 2 months showed no residual fluid collection. Conclusions: This case indicates malignant perirenal PEComa as a rare cause of Wunderlich syndrome and underscores the need to anticipate duodenal injury in right upper-pole renal tumors with massive hematoma or severe adhesions, consider early conversion for safer duodenal mobilization, and promptly evaluate persistent postoperative inflammation with markedly elevated urine amylase (hyperamylasuria).