Soft tissue sarcomas.

Sarcomas are a heterogeneous group of rare tumors that arise predominantly from the embryonic mesoderm. They present most commonly as an asymptomatic mass originating in an extremity but can occur anywhere in the body, particularly the trunk, retroperitoneum, or the head and neck. Pretreatment radiologic imaging is critical for defining the local extent of a tumor, staging the disease, guiding biopsies, and aiding in diagnosis. Core-needle biopsy is the preferred biopsy technique for diagnosing soft tissue sarcomas. The American Joint Committee on Cancer (AJCC) staging system for soft tissue sarcomas is based on histologic grade, the tumor size and depth, and the presence of distant or nodal metastases. Despite improvements in local control rates with wide local resections and radiation therapy, metastasis and death remain a significant problem in 50% of patients who present with high-risk soft tissue sarcomas. The most common site of metastasis is the lungs, and metastasis generally occurs within two to three years after the completion of therapy. Progress in the molecular characteristics of these tumors should in the near future translate into molecularly based therapies that can be incorporated into standard treatment strategies.