M.C. retroperitoneal tumour is -
Ans is 'b' ie Liposarcoma The most common primary malignancy of the retroperitoneum is sarcoma.(Ref Sabiston) "In the retroperitoneal location, well-differentiated and dedifferentiated liposarcoma and leiomyosarcoma are the most common histiotypes, whereas in the visceral location, GISTs are found most commonly."- Devita's Oncology
Fibrosarcoma
Liposarcoma
Dermoid cyst
Rhabdosarcoma