[Soft tissue sarcoma of the extremities-imaging, biopsy planning, and pitfalls in radiology]

Radiology is integral to the multimodal diagnostic and treatment pathway of extremity soft tissue sarcomas in DGK-certified sarcoma centers (DGK: Deutsche Krebsgesellschaft, German Cancer Society), working in close interdisciplinary collaboration with sarcoma surgery, pathology, radiation oncology, and medical oncology.

Treatment decisions rely on guideline- and recommendation-based imaging and histological confirmation by biopsy. When clinical warning signs (red flags) are present, radiological imaging is essential for triage and early referral to a sarcoma center. For local staging, magnetic resonance imaging (MRI) is the modality of choice. It provides crucial information for diagnosis, prognosis, and treatment within the sarcoma board and serves as the basis for adequate biopsy planning.

Diagnostic pitfalls arise from overlapping MRI appearances, particularly within the lipomatous spectrum and in lesions with myxoid and cystic patterns. A further focus is on avoidable procedural biopsy errors, inadequate targeting, and an inadequate biopsy tract that is not amenable to en bloc resection or that contaminates additional compartments/joints or neurovascular structures.

The article outlines a risk-adapted diagnostic approach and provides practice-oriented principles for biopsy planning. It highlights typical problem MRI constellations to avoid misdiagnosis and underestimation of malignancy (grading), ultimately establishing optimal prerequisites for therapy.