Soft tissue sarcoma (STS) is a heterogeneous collection of over 80 histologically distinct types of tumors with distinct etiologies, behavior, and prognosis. They are extremely rare, comprising <1% of all human malignancies. Owing to both the variability of clinical behavior and the rarity of these tumors, STS poses a therapeutic challenge to oncologists. Retroperitoneal STS (RPS) is particularly difficult to treat because the primary tumors become very large prior to presentation and as a result render surgical resection technically demanding. Adjuvant therapies such as chemotherapy and radiation offer little benefit in addition to surgery; thus resection to negative margins remains the mainstay of treatment. History and physical exam are focused on identifying risk factors for sarcoma, potential genetic syndromes that may underlie the presentation, and risk stratifying the patient for interventions. In most cases, a biopsy is obtained to confirm the diagnosis prior to surgery. Surgical resection often requires resection of adjacent organs that are invaded by the tumor and as a result are technically demanding, high-risk procedures. After surgery, patients are followed closely for years (often life-long) with cross-sectional imaging to detect recurrence as this is unfortunately commonplace for RPS.