Which of the following is biphasic tumor?

ANSWER: (B) Synovial sarcomaREF: Robbins 8th ed chapter 26SYNOVIAL SARCOMA:Cell of origin is still unclearAlthough the term synovial sarcoma implies an origin from the joint linings, less than 10% are intra-articularFourth most common sarcomaMost occur in the 20s to 40s.The majority develop in the deep soft tissue and about 60% to 70% involve the lower extremity, especially around the knee and thigh.Synovial sarcomas are morphologically biphasic or monophasic. The histologic hallmark of biphasic synovial sarcoma is dual lines of differentiation (i.e., epithelial-like and mesenchymal-like).A characteristic feature when present is calcified concretions that can sometimes be detected radiographically.Immunohistochemistry is helpful in identifying these tumors, since the tumor cells yield positive reactions for keratin and epithelial membrane antigen, differentiating them from most other sarcomas.chromosomal translocation t(x;18)(p11;q11)Synovial sarcomas are treated aggressively with limb-sparing therapy and frequently chemotherapy