[Soft tissue sarcomas: current data in the field of pathology].

Over the last fifteen years, pathology underwent significant changes in the field of soft tissue tumours. They were related to considerable advances in molecular biology and genetics. New data led to the revision of the WHO classification. Malignant fibrous histiocytoma is no longer considered as an entity. It has split up into several subgroups belonging to liposarcomas, leiomyosarcomas or undifferentiated sarcomas. Haemangiopericytoma underwent reappraisal and was put in the same category as solitary fibrous tumour. Many tools have improved. Immunohistochemistry performed with new antibodies had its specificity increased, and became appropriate for the prediction of therapeutic response in some cases, e.g. CD117 detecting mutations of the c-kit proto-oncogen in gastro-intestinal stromal tumours. Refinement of the techniques allows accurate diagnoses from core needle biopsies. Surgical specimens are collegially examined by surgeons and pathologists with special attention paid to resection margins. Although bound by some limitations, the grading system of the French Federation of Cancer Centers has currently remained the best predictor of metastasis-free survival and overall survival of patients. It is based on an assessment of three parameters: differentiation, amount of necrosis, and mitotic count of tumours. The pathologist sets up a diagnosis, and actively takes part in the prediction of the prognosis and therapeutic response. He is one of the major participants in decision making for multimodal treatment of sarcomas.