Accuracy and Safety of Ultrasound-Guided Core Needle Biopsy of Soft Tissue Tumors in an Outpatient Setting: A Sarcoma Center Analysis of 392 Consecutive Patients.

Background: The aim of this study was to investigate diagnostic accuracy, safety and histologic results of ultrasound guided core needle biopsy (CNB) in patients with soft tissue lesions (STL) at a tertiary referral center.

Methods: A retrospective analysis of all consecutive patients undergoing ultrasound guided CNB for STL at our sarcoma outpatient service between January 2015 and August 2020 was performed.

Results: A total of 392 patients were identified. Main histologic entities were sarcomas, lipomas and desmoid tumors. Biopsy was performed in an outpatient setting in 87.6% of the cases. Conclusive biopsies were obtained in 88.5% of the cases. In patients who underwent surgical resection after CNB, the concordance of dignity, tumor entity and histopathological grading between biopsy and resection specimen were 97.2%, 92.7% and 92.5% respectively. The risk of inconclusive CNB was highest in intraabdominal or retroperitoneal tumors (19.5%) and lowest in lesions at the lower extremity (4.4%). Major complications after CNB occurred in three cases (0.8%). No case of biopsy tract seeding was observed during the study period.

Conclusions: Ultrasound guided CNB for STL at first presentation in a dedicated surgical outpatient setting is a safe procedure and yields a high diagnostic accuracy.