Percutaneous CT-guided bone biopsy: diagnosis of malignancy in lesions with initially indeterminate biopsy results and CT features associated with diagnostic or indeterminate results.

Abstract

The purpose of our study was to determine the proportion of bone lesions with indeterminate results after initial percutaneous CT-guided bone biopsy that ultimately are found to be malignant and whether CT features are associated with diagnostic outcomes. The results of 800 consecutive percutaneous CT-guided bone biopsies performed at a tertiary cancer center were reviewed. The initial histopathologic diagnosis was classified as diagnostic or indeterminate. On the basis of follow-up information, indeterminate results were subcategorized as benign, malignant, or persistently indeterminate. Two readers independently analyzed the CT images. Initial percutaneous CT-guided bone biopsy was diagnostic in 69% and indeterminate in 31%. Malignancy was diagnosed in 90% of initially diagnostic results. In lesions with initially indeterminate results, a diagnosis was subsequently made in 62%; 39% of subsequent diagnoses were malignant as of the last available follow-up. CT features associated with diagnostic results included cortical destruction and large extraosseous mass (p < 0.05). More lesional sclerosis and presence of fat were associated with indeterminate results (p < 0.001). CT features associated with malignant results included less-extensive sclerosis and lesser sclerotic rim (p < 0.05). Increased age, female sex, and a cancer history were associated with higher risk of malignancy among patients with diagnostic results at initial biopsy. Bone lesions that initially yield indeterminate results at percutaneous CT-guided bone biopsy often are subsequently shown to be malignant; vigorous pursuit of a diagnosis is recommended if initial results are indeterminate. Lesions showing fat or more sclerosis are more likely to be indeterminate; lesions with less sclerosis or smaller sclerotic rim are more likely to yield malignant results.