Prognostic factors and staging for soft tissue sarcomas: an update.

Soft tissue sarcoma (STS) staging is a constantly evolving process. Grading is still of utmost importance and has been adapted into a three-tier system. The STS most difficult to categorize are those with uncertain malignant potential, such as solitary fibrous tumors, gastrointestinal stromal tumors, and glomus tumors, some of which have developed completely separate staging systems and may not even be considered sarcomas. Beyond the current TNM staging system, a multitude of prognostic factors for STS will continue to be discovered and ultimately incorporated into future revisions of the staging system.