Tham khảo tài liệu 'chapter 094. soft tissue and bone sarcomas and bone metastases (part 2)', y tế - sức khoẻ, y học thường thức phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 094. Soft Tissue and Bone Sarcomas and Bone Metastases Part 2 Classification Approximately 20 different groups of sarcomas are recognized on the basis of the pattern of differentiation toward normal tissue. For example rhabdomyosarcoma shows evidence of skeletal muscle fibers with cross-striations leiomyosarcomas contain interlacing fascicles of spindle cells resembling smooth muscle and liposarcomas contain adipocytes. When precise characterization of the group is not possible the tumors are called unclassified sarcomas. All of the primary bone sarcomas can also arise from soft tissues . extraskeletal osteosarcoma . The entity malignant fibrous histiocytoma includes many tumors previously classified as fibrosarcomas or as pleomorphic variants of other sarcomas and is characterized by a mixture of spindle fibrous cells and round histiocytic cells arranged in a storiform pattern with frequent giant cells and areas of pleomorphism. For purposes of treatment most soft tissue sarcomas can be considered together. However some specific tumors have distinct features. For example liposarcoma can have a spectrum of behaviors. Pleomorphic liposarcomas and dedifferentiated liposarcomas behave like other high-grade sarcomas in contrast well-differentiated liposarcomas better termed atypical lipomatous tumors lack metastatic potential and myxoid liposarcomas metastasize infrequently but when they do have a predilection for unusual metastatic sites containing fat such as the retroperitoneum mediastinum and subcutaneous tissue. Rhabdomyosarcomas Ewing s sarcoma and other small-cell sarcomas tend to be more aggressive and are more responsive to chemotherapy than other soft tissue sarcomas. Gastrointestinal stromal cell tumors GISTs previously classified as gastrointestinal leiomyosarcomas are now recognized as a distinct entity within soft tissue sarcomas. Its cell of origin resembles the interstitial cell of Cajal which controls peristalsis. The majority of malignant .
