Abstract
Soft tissue sarcomas (STS) in the retroperitoneum are rare and account for a small percentage of adult STS. The most common type is liposarcoma, while fibrosarcoma and extra skeletal Ewing sarcoma (EES) are rarer. Retroperitoneal fibrosarcoma's are extremely uncommon. Diagnosis requires a comprehensive evaluation including clinical, radiological, histopathological, and immunohistochemical examinations to determine the specific subtype of STS in the retroperitoneum. A 76-year-old male presented with a large retroperitoneal tumour. Surgery successfully removed the tumor which was diagnosed as dedifferentiated liposarcoma based on microscopic analysis and positive vimentin and MDM2 markers. We also report a case of 69-year-old male with a retroperitoneal mass that was ultimately diagnosed as adult fibrosarcoma after ruling out other possibilities. The third case was of 55-year-old female who presented with left lumbar pain, backache, and weight loss. Imaging revealed a retroperitoneal mass with hepatic metastasis. Histopathological examination and IHC analysis confirmed the diagnosis of extraskeletal Ewing sarcoma. The importance of accurate diagnosis through histopathological examination and immunohistochemical analysis is emphasized for effective management and prognosis.