Ultrasound guided core needle biopsy of soft tissue tumors; a fool proof technique?

Aim: To assess technical and lesion related factors affecting the quality of ultrasound guided core needle biopsy (CNB) of musculoskeletal soft tissue tumors.

Materials And Methods: Data of 223 CNBs were evaluated in a retrospective study. Diagnostic yield was calculated for all lesions on the basis of lesion location (extremity/torso), examiner, biopsy needle gauge/length and number of acquired samples. Diagnostic accuracy was calculated for surgical lesions (n= 113) based on final specimen histology. Chi-square test based Phi-coefficient calculations were performed to search for associations between each factor and diagnostic yield.

Results: Overall diagnostic yield was 94.6%. There was no significant difference in diagnostic yield between specialist biopsies (96.8%) and resident biopsies (93.1%), between lesions located in the extremities (94.9%) and lesions in the torso (93.8%) and on the basis of needle gauge or number of acquired cores. Diagnostic accuracy was 100% for surgical lesions. The only factor influencing the quality of CNB was lesion composition (repeat biopsies in myxoid and/or inhomogeneous lesions).

Conclusion: The most important aspects to achieve constant high quality results with ultrasound guided CNBs in the work-up of musculoskeletal soft tissue tumors are expertise concerning identification and targeting of viable tumor components and strict adherence to a quality controlled biopsy procedure. Once this is achieved, technical factors have almost no effect on the quality of CNB.