[Classification of soft tissue tumors and current approach to pathologic diagnosis]

Soft tissue sarcomas are rare malignant tumors arising from soft tissues of mesenchymal origin. These tumors can develop from any site in the body, including the extremities, trunk, retroperitoneum, and the head and neck. Factors such as histologic subtype and grade, as well as patient age, tumor size, location and clinical stage, determine the specific approach to management and patient outcome. Early detection and treatment based on accurate diagnosis are the basic principles of the management of soft tissue sarcomas. Although the histological grading of soft tissue sarcomas is based on the French Federation Nationale des Lutte Contre le Cancer (FNCLCC) system, it seems to easy to use the histological grading based on the MIB-1 labeling index. The definitive diagnosis of soft tissue tumors is aided by appropriate immunohistochemical examination and molecular analysis. In particularly, molecular analysis of tumor-specific chromosomal translocations using FISH or RT-PCR methods offers a useful adjunct to the accurate diagnosis of soft tissue tumors. However, many studies have indicated a growing number of fusion gene variations in each tumor type. This article reviews and discusses problems in the diagnostic pathology of soft tissue tumors with newly useful pathological methods.