Person:

Wu, Jim

Objective: To assess the utility of repeat image guided core needle biopsy (CNB) of musculoskeletal lesions in the setting of an initially non-diagnostic CNB biopsy. Materials and Methods: Following IRB approval, a retrospective review was conducted of 1302 consecutive CNBs performed on bone or soft tissue lesions at a single institution. All cases where a repeat biopsy of the same lesion was requested by the referring physician due to non-diagnostic biopsy results were included in the study. Tumor characteristics such as lesion size and type (bone versus soft tissue) were correlated with diagnostic yield on repeat biopsy. Technical factors including the modality used, number of passes performed, gauge of the biopsy device, radiologist performing the procedure and portion of the lesion biopsied were also correlated. Results: Of the 1302 CNBs performed, 26 (2.0%) were referred for repeat biopsy. A diagnosis was obtained in 38.5% (10/26) of cases following a repeat CNB. In 5 out of the 26 cases (19.2%), a repeat CNB yielded malignancy. Overall, eleven cases were ultimately of malignant histology, of which 5 (45.4%) were diagnostic following rebiopsy. Fourteen cases were benign, of which 5 (35.7%) were diagnostic following rebiopsy. One case was lost to follow-up. A statistically significant difference in diagnostic yield was found between cases where an increased number of passes were made between the initial and repeat (p=0.047) biopsies. Conclusion: Repeat core needle biopsy of initially non-diagnostic musculoskeletal lesions can be potentially useful. Increasing the number of passes on the second biopsy attempt is recommended.

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.