Diagnostic concordance between ultrasound-guided core needle biopsy and surgical resection specimens for histological grading of extremity and trunk soft tissue sarcoma

Objective Determination of accurate histological grade impacts on management for soft tissue sarcomas (STSs). Although ultrasound-guided core needle biopsy (US-CNB) accurately establishes tumour subtype compared with surgical specimens, the concordance for tumour grade is uncertain. The aim of this study was to assess the concordance between US-CNB and surgical resection specimens for tumour grade in trunk and extremity STS. Materials and methods Retrospective review of consecutive patients presenting with extremity/trunk STS. Data collected included patient age, gender, lesion location, US-CNB diagnosis and grade, and surgical histology and grade. The histological diagnosis and tumour grade from US-CNB was compared with surgical resection histology. Results A total of 118 patients were included, 76 males and 42 females with a mean age of 54 years (range 10 months-90 years old). STS size ranged from 26 to 350 mm (mean 89.5 mm). All US-CNB procedures were performed with a 14G biopsy needle with a mean number of 5 passes. First US-CNB was diagnostic for STS in all patients, and provided adequate tissue for tumour grading in all but one patient. Histological tumour subtype on US-CNB matched surgical specimens in all cases, with 25 (21.2%) STS being low grade and 93 (78.8%) high grade. The concordance for tumour grade was 96.6%, with no difference between low- and high-grade STSs (p > 0.05). The 4 cases of mismatch were considered low grade on US-CNB, but subsequently high grade on surgical resection. Conclusion US-CNB of STS can reliably predict histological tumour grade compared with surgical resection specimens, thus allowing confident treatment decisions to be made.