Benign soft tissue tumors can be slow growing, with low chance for recurrence, or aggressive, with higher chance for recurrence. An examples of a slow growing tumor would be lipoma. Examples of aggressive benign tumors would be fibromatosis or pigmented villonodular synovitis (PVNS).
Sometimes the location (such as within a joint for PVNS) or the appearance on MRI scans (such as with lipoma), can accurately predict the diagnosis. However, biopsy is usually required.
Usually, no additional muscle is removed for benign soft tissue tumors ("marginal" resection).

Most malignant soft tissue tumors of the extremities are sarcomas. In general, sarcomas respect anatomic boundaries and, thus, surgical removal of the tumor with an intact covering ("margin") of normal tissues is adequate to prevent the tumor from recurring. In planning surgery, the "grade" ("grading" and "staging") of the tumor is taken into account. The higher the grade, the higher the risk of recurrence and more aggressive surgical and non-surgical treatment is required.

In certain situations, tissue from another party of the body is used to fill the defect. This can be a nearby muscle that is rotated into position or a piece of muscle detached entirely and sewn into place with its feedling blood vessel intact ("free flap"). This type of procedure is performed in conjunction with a plastic surgeon.

Radiation administered before surgery is referred to as "neoadjuvant" radiation (and as "adjuvant" radiation when it is administered after surgery).
For bone sarcomas, both neoadjuvant and adjuvant chemotherapy are given. This practice was established many years ago when it was found that it allowed for limb-sparing surgery in situations where the size of the tumor may have otherwise required amputation and that it did not significantly increase surgical complications
For soft tissue sarcomas, neoadjuvant radiotherapy has been used for high grade (rapidly growing) soft tissue sarcomas with the same rationale.