Histological grading and MIB‐1 labeling index of soft‐tissue sarcomas

Soft-tissue sarcomas or malignant soft-tissue tumors are malignant tumors arising from soft tissues of mesenchymal origin. These soft-tissue tumors can develop from any site in the body, including the extremities, trunk, retroperitoneum, or the head/neck region. In Japan, soft-tissue sarcomas are rarely encountered, with an incidence of approximately 2 per 100 000 population. Diverse types (more than 30 types) of soft-tissue sarcomas are known. Pathological examination of biopsy or resected specimens is indispensable for a definitive diagnosis of soft-tissue sarcomas. Needless to say, early detection and treatment based on accurate diagnosis are the basic principles of the management of soft-tissue sarcomas. The purpose of the present paper was to address the histological grading of soft-tissue sarcomas (the most important histopathological prognostic factor for this type of sarcoma) based on the French Fédération Nationale des Centres de Lutte Contre Ie Cancer (FNCLCC) system, the histological grading of this type of sarcoma based on the MIB-1 labeling index (an immunohistochemical marker of cell proliferation; MIB-1 system), precautions that must be taken while evaluating the degree of malignancy and the relationship of the grade with other clinicopathological factors.