Percutaneous CT-guided needle biopsies of musculoskeletal tumors: a 5-year analysis of non-diagnostic biopsies.

Objective: To study non-diagnostic CT-guided musculoskeletal biopsies and take steps to minimize them. Specifically we asked: (1) What malignant diagnoses have a higher non-diagnostic rate? (2) What factors of a non-diagnostic biopsy may warrant more aggressive pursuit? (3) Do intra-procedural frozen pathology (FP) or point-of-care (POC) cytology reduce the non-diagnostic biopsy rate?

Materials And Methods: This study was IRB-approved and HIPAA-compliant. We retrospectively reviewed 963 consecutive CT-guided musculoskeletal biopsies. We categorized pathology results as malignant, benign, or non-diagnostic and recorded use of FP or POC cytology. Initial biopsy indication, final diagnosis, method of obtaining the final diagnosis of non-diagnostic biopsies, age of the patient, and years of biopsy attending experience were recorded. Groups were compared using Pearson's χ(2) test or Fisher's exact test.

Results: In all, 140 of 963 (15%) biopsies were non-diagnostic. Lymphoma resulted in more non-diagnostic biopsies (P < 0.0001). While 67% of non-diagnostic biopsies yielded benign diagnoses, 33% yielded malignant diagnoses. Patients whose percutaneous biopsy was indicated due to the clinical context without malignancy history almost always generated benign results (96%). Whereas 56% of biopsies whose indication was an imaging finding of a treatable lesion were malignant, 20% of biopsies whose indication was a history of malignancy were malignant. There was no statistically significant difference in the nondiagnostic biopsy rates of pediatric versus adult patients (P = 0.8) and of biopsy attendings with fewer versus more years of experience (P = 0.5). The non-diagnostic rates of biopsies with FP (8%), POC cytology (25%), or neither (24%) were significantly different (P < 0.0001).

Conclusion: Lymphoma is the malignant diagnosis most likely to result in a non-diagnostic biopsy. If the clinical and radiologic suspicion for malignancy is high, repeat biopsy is warranted. If the clinical context suggests a benign lesion, a non-diagnostic biopsy may be considered reassuring. Frozen pathology may decrease the non-diagnostic biopsy rate.