Surgical pathology and biopsy of Sarcomas

Sarcomas account for approximately 1% of malignant tumors in adults. Their rarity contrasts with their remarkable diversity, as nearly 150 distinct histological subtypes have been described. The majority (≈80%) arise in soft tissues, while 15% affect the bones and 5% the viscera.
Diagnosis relies on the microscopic examination of a percutaneous biopsy, the interpretation of which requires specialized expertise that integrates clinical data, imaging, and molecular biology. From the very first radiological suspicion, referral to a NETSARC+ expert center is imperative. Moreover, any diagnosis of sarcoma, mesenchymal tumor of intermediate malignancy, desmoid tumor, or gastrointestinal stromal tumor (GIST) established outside the network must be systematically reviewed by a specialized pathologist. This responsibility falls to the Reference Network for Sarcoma Pathology (RRePS) for soft tissue tumors, and to the Reference Network for the management of bone sarcomas and rare bone tumors (RESOS) for skeletal locations.
Advances in molecular biology continue to reshape the classification of sarcomas. The latest edition of the World Health Organization (WHO) classification now incorporates genetic data, enabling the identification of new entities as well as the reclassification of preexisting ones. At the same time, the development of specific immunohistochemical markers derived from these discoveries allows for faster, more reliable, and economically accessible diagnosis.
Finally, innovative approaches are emerging, notably the application of artificial intelligence tools to the analysis of virtual slides, with the aim of refining the prognostic stratification of gastrointestinal stromal tumors.