Recurrent giant retroperitoneal dedifferentiated liposarcoma requiring challenging multiorgan resection: a case report.

Background: Dedifferentiated liposarcoma is a rare, aggressive subtype of liposarcoma known for its high recurrence rate and local invasiveness. This case demonstrates the challenges in managing a rapidly recurring dedifferentiated liposarcoma and underscores the need for improved surveillance and additional treatment options.

Case presentation: A 57-year-old non-Hispanic white male presented in November 2023 with a 2-month history of intermittent fevers, nonproductive cough, and lower abdominal discomfort. Imaging revealed a 12 cm × 12 cm × 16 cm retroperitoneal mass, confirmed to be a high-grade dedifferentiated liposarcoma. Initial surgical resection in December 2023 removed the tumor, which was densely adhered to the left kidney. Despite adjuvant chemotherapy, follow-up imaging in July 2024 showed tumor recurrence with a 15 cm × 14 cm × 21 cm multiloculated cystic mass extending from the spleen to the lower pole of the kidney, as well as a 12 cm × 6 cm × 15 cm mass inferior to the left kidney. Owing to the extensive local invasion, a second surgery in August 2024 required a left nephrectomy, splenectomy, hemicolectomy, and distal pancreatectomy. The tumor's proximity to the abdominal aorta and invasion into the psoas muscle posed significant surgical challenges, requiring careful resection.

Conclusion: This case highlights the aggressive nature of high-grade dedifferentiated liposarcoma and its resistance to chemotherapy. Surgical resection remains the primary treatment option, but the recurrence emphasizes the need for more effective therapies. The case further illustrates the complexity of multiorgan involvement in recurrent dedifferentiated liposarcoma and the critical role of experienced oncologic surgeons in managing these cases. More research is necessary to develop alternative treatments that can better control tumor progression and improve patient outcomes.