Retroperitoneal Fibrosarcoma: A Rare Case Report.

Retroperitoneal sarcomas are rare tumors ranging from only 1% to 2% of all solid malignancies. Among all sarcomas, most of these occur outside the retroperitoneum. Only 10-20% of sarcomas are retroperitoneal sarcomas, and the overall incidence is 0.3-0.4% per 100,000 of the population. The diagnosis and treatment of retroperitoneal sarcomas are challenging because the tumors are quite rare and usually present in latter stages of the disease in an anatomically complex location. A rare case of recurrent retroperitoneal fibrosarcoma in a 23-year-old male presented as a mass per abdomen. Retroperitoneal sarcomas are malignant tumors arising from mesenchymal cells, which are usually located in muscle, fat, and connective tissues.