Introduction

Soft tissue sarcomas (STS) constitute a broad group of tumors derived from mesenchymal tissues comprised of structural and connective tissue including muscle, endothelium, synovium, fat, lymphatics and fascia. The tumors generally acquire their name from the tissue they most closely resemble. There are up to fifty histologic subtype variants with their names changing as more information is gained at a cellular and molecular level.[1] These tumors can occur throughout the body and in all age groups. As a group they constitute the fifth most common malignancy in childhood and roughly 5-7% of pediatric cancers.

Sarcomas are divided into rhabdomyosarcoma (RMS) and nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) with each representing approximately 50% of the total number of sarcomas.[2] A primary differentiation is that RMS is relatively sensitive to radiation and chemotherapy while NRSTS are less sensitive to these modalities. The exceptions are synovial cell sarcoma, infantile fibrosarcoma, and a few other etiologicies which are sensitive to standard chemotherapy. Additionally desmoplastic small round cell tumor (DSRCT), while having overall poor prognosis, does typically initially respond well to Ewing’s-type chemotherapy.

These individual tumor histologies are very rare and therefore attempts to study them have necessitated grouping them into the broad classification of NRSTS in order to perform clinical trials with sufficient power and gain valuable information about prognosis and different potential treatment strategies. As the genetics and biology of the various subtypes of sarcomas are elucidated, the term NRSTS most likely will fall out of favor. Evidence for the optimal treatment of these rare tumors is in evolution and successful treatment of patients with NRSTS depends on a multidisciplinary approach to therapy including oncology, surgery, radiation oncology, radiology, and pathology.