Laparoscopic spleen-preserving distal pancreatectomy using the Warshaw technique for retroperitoneal dedifferentiated liposarcoma with direct pancreatic invasion: a case report

Introduction and importance: Retroperitoneal dedifferentiated liposarcoma is a rare soft-tissue sarcoma typically presenting as a large mass. Small tumors lacking a distinct fatty component may mimic pancreatic or peripancreatic neoplasms, complicating preoperative diagnosis. Presentation of case: A 58-year-old man was referred after a routine examination revealed a mass adjacent to the pancreatic tail. He had lost 4 kg over 6 months but was asymptomatic. Contrast-enhanced computed tomography revealed a 34 mm heterogeneously enhancing lesion abutting the splenic vessels, while magnetic resonance imaging showed a mixed solid-cystic mass without main pancreatic duct dilatation. Endoscopic ultrasound-guided tissue acquisition was non-diagnostic; however, cytology was suspicious for malignancy (class IV). Positron emission tomography/computed tomography revealed intense fluorodeoxyglucose uptake (SUVmax, 13.9). Because malignancy could not be excluded, laparoscopic resection was performed. Intraoperatively, the tumor was inseparable from the pancreas, requiring en bloc spleen-preserving distal pancreatectomy using the Warshaw technique. Clinical discussion: Histopathology confirmed retroperitoneal dedifferentiated liposarcoma with pancreatic invasion. Immunohistochemistry was positive for p16, MDM2, and CDK4; resection margins were negative. A grade B postoperative pancreatic fistula necessitated drain replacement; the patient was discharged on postoperative day 22. He remained disease-free at 3 months. This case highlights diagnostic challenges in fat-poor dedifferentiated liposarcoma and the importance of complete resection when adjacent organs are involved. Conclusion: Retroperitoneal dedifferentiated liposarcoma should be considered in the differential diagnosis of atypical tumors adjacent to the pancreatic tail. When pancreatic invasion precludes a safe dissection, laparoscopic en bloc distal pancreatectomy can achieve complete resection while preserving the spleen in carefully selected patients.