The role of needle biopsy for focal bone lesions with complete fluid-fluid levels on magnetic resonance imaging.

OBJECTIVE

To assess the value of image-guided needle biopsy of bone lesions completely filled with fluid-fluid levels (FFLs) on magnetic resonance imaging (MRI) and the safety of primary surgical curettage.

MATERIALS AND METHODS

The radiology database was searched for all reports containing "fluid level" from 1998 to 2011 and the imaging was reviewed retrospectively. Inclusion criteria were patients with bone lesions completely filled with FFLs on MRI (defined as FFLs on every axial and/or sagittal T2-weighted or Short Tau Inversion Recovery (STIR) sequence). The pathology database was then reviewed for the outcome of needle biopsy (n=14) and for the outcome of surgical curettage, either post-biopsy or primary (n=52).

RESULTS

There were 53 patients (mean age 18 years; M=34, F=19). Fourteen patients underwent percutaneous needle biopsy, which was diagnostic in five (36 %) and non-diagnostic in nine (64 %). Fifty-two patients had surgical curettage/resection, which was diagnostic in 50 (96 %) and non-diagnostic in two (4 %). All lesions were benign; 78 % were aneurysmal bone cysts (ABC), 8 % were lesions with ABC change, and 14 % were simple bone cysts.

CONCLUSIONS

Our results suggest that patients with bone lesions completely filled with FFLs on MRI are almost certain to be benign, provided that the clinical and radiological features are not atypical. Percutaneous needle biopsy in such cases is unlikely to be of value and these lesions can be safely managed with primary surgical curettage.