Image-Guided Core Needle Biopsy of Adipocytic Tumors: Diagnostic Accuracy and Concordance With Final Surgical Pathology

Abstract

Objective. Diagnostic accuracy of core needle biopsy (CNB) for adipocytic tumors can be low due to sampling error from these often large, heterogeneous lesions. The purpose of this study is to evaluate the diagnostic accuracy of image-guided CNB for various adipocytic tumors with comparison to excisional pathology.

Materials and Methods. Adipocytic tumors (N=79) of all adult patients undergoing image-guided CNB and subsequent surgical excision of an adipocytic tumor at a tertiary referral center between 2005 and 2019 were studied. Pathologic diagnoses based on CNB were compared with final pathology at surgical excision. Diagnostic accuracy was calculated for 3 categories: benign lipomatous tumors (lipoma, lipoma variants, hibernomas), atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDL), and liposarcomas (myxoid, dedifferentiated, pleomorphic, unspecified).

Results. Pathologic diagnosis from CNB was concordant with excisional diagnosis in 75 of 79 adipocytic tumors (95%). Diagnostic accuracy was significantly different for ALT/WDL when compared with benign lipomatous tumors and liposarcomas (p<0.002). The CNB results of all benign lipomatous tumors (N=29) and liposarcomas (N=29) were concordant with final pathology after excision (100%). Of the 21 tumors diagnosed as ALT/WDL at CNB, 17 were concordant with final surgical pathology (81%); three tumors were upgraded to dedifferentiated liposarcoma and one tumor was upgraded to myxoid liposarcoma.

Conclusions. Diagnostic accuracy of CNB for adipocytic tumors is high, especially for benign lipomatous tumors and liposarcomas. However, 19% of ALT/WDL at CNB were upgraded after excision. Awareness of this limitation should help guide clinical management especially in cases of ALT/WDL where surgery is not planned.