This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Neoplasia), Subject name: Surgery
Most common tumor of Retro-peritoneum: 
Select and explain. 
A. Stroma, B. Sarcoma, C. Teratoma, D. Retro-teratoma
B: Sarcoma
Answer: B: Sarcoma 
Explanation: Ans. (b) SarcomaRef: Bailey and love 26th ed. ch. 61/985* One third of malignant tumors that arise in the retroperitoneum are sarcomas, and approximately 15% of soft tissue sarcomas arise in the retroperitoneum.* Retroperitoneal sarcomas are malignant tumors arising from mesenchymal cells, which are usually located in muscle, fat, and connective tissues. Retroperitoneal sarcomas have varying clinical courses depending on their histologic subtype and grade.