ABSTRACT
Soft tissue tumors (STT) may be benign or malignant, and a variety of borderline lesions are also recognized. The ratio of benign to malignant tumor is more than 100:1. Malignant STT arising from mesoderm are referred to as ‘sarcomas’. Developments in pathology suggest that some tumors, conventionally considered sarcoma, do not belong under the classical description. The conventional definition, in Webster’s International Dictionary, includes ‘any of various malignant tumors that begin in connective tissue or in tissue developed from the mesoblast’. According to this definition, some tumors treated as sarcomas, particularly by clinicians, such as primitive neuroectodermal tumor (PNET)/Ewing’s sarcoma and most malignant peripheral nerve sheath tumors, technically are not sarcomas. The histopathologic classification is clearly evolving, but because of current usage, the majority of lesions historically considered as sarcoma will continue to be described as such, despite identification of cells of origin other than the mesoblast.
