Diagnostic yield of percutaneous image-guided tissue biopsy of focal hepatic lesions in cancer patients: ten percent are not metastases from the primary malignancy.

BACKGROUND The diagnostic yield was evaluated of percutaneous image-guided tissue biopsy of hepatic lesions identified on computed tomography performed for staging of a primary malignancy, and it was determined how often the biopsy result was unexpectedly negative, benign, or secondary to a second unknown malignancy. METHODS In a retrospective investigation from 1998 through 2008, 580 patients with primary malignancies had indeterminate focal hepatic lesions and underwent percutaneous image-guided biopsy; 369 patients had lesions in their liver at first cross-sectional imaging, performed for staging; 211 patients had a negative liver imaging study, followed by the subsequent appearance of at least 1 indeterminate suspicious lesion. The results of percutaneous image-guided tissue biopsies were compared with the histology of the primary malignancy. RESULTS Liver biopsies were performed in 580 patients (288 men and 292 women; age, 25-92 years; mean age, 61 years). The most common primary malignancies were pancreatic (n = 96), breast (n = 85), melanoma (n = 57), esophageal (n = 51), lung (n = 47), colorectal (n = 37), and urothelial tumors (n = 26). Biopsy results were positive for malignancy in 528 (91%) cases. Among the positive biopsies, 29 (5%) cases had pathology results different from the primary tumor. Of the 52 biopsies negative for malignancy, 20 yielded a specific benign diagnosis, and 32 were nondiagnostic. CONCLUSIONS If all liver lesions had been assumed to be metastases, as expected secondary to the known primary tumor, then the true or presumed alternate diagnosis would have been missed in 60 (10.3%) of the 580 cases. The authors did not attempt to determine whether actual clinical management changed based on these 60 liver biopsy results, so this number is an upper bound on management change. On the basis of these results, and given the minimal complication rate of liver biopsy, the authors suggest that liver biopsy should still be performed in the types of cases studied here, despite the finding that the vast majority of biopsies produced the expected result and presumably did not change patient management.