Intraprocedural Percutaneous Biopsy Preceding Ablation of Osteoid Osteoma: Diagnostic Yield and Predictors of Adequacy

Purpose: To examine the diagnostic yield and predictive factors of biopsy adequacy of intraprocedural percutaneous biopsy performed at the time of radiofrequency ablation of osteoid osteoma (OO)

Materials and Methods: After local institutional review board approval, patients who underwent percutaneous biopsy at the time of radiofrequency ablation (RFA) of OO between June 2010 and June 2017 were retrospectively identified. Patient records and imaging were reviewed for patient demographics, lesion size and location, presence of periosteal reaction, nature of the lesions nidus, distance between lesion and overlying cortex, distance of bone traversed to reach the lesion, needle trajectory, needle type and size, number of core samples obtained, technical success, biopsy yield, and clinical outcomes. Multivariate logistic regression was performed to identify potential predictive factors of adequate diagnostic yield.

Results: A total of 42 cases were identified between June 2010 and June 2017. All patients had intraprocedural biopsy performed immediately before RFA. Each patient had one lesion that was targeted for biopsy and treatment. The lesions were located in the femur (14 of 42), tibia (14 of 42), ankle or foot (6 of 42), pelvic girdle (3 of 42), humerus (3 of 42), shoulder girdle (1 of 42), and fibula (1 or 42). The lesions had an average size of 6.28 mm ± 2.17, with range of 3 to 11 mm. Core biopsies were performed with two needle types ranging from 11 to 15 gauge with an average number of cores samples of 1.8 ± 1. A total of 22 of 42 (52.3%) of the biopsies were adequate for histologic diagnosis of OO. Bivariate analysis demonstrated a significant correlation between presence of an osteoid matrix (P = 0.03), obtaining more than one core sample (P = 0.03), the needle passing through the nidus (P = 0.0003), and biopsy adequacy. On multivariate logistic regression analysis, only the presence of a nidus matrix is found to be a significant predictor of adequate biopsy (P = 0.04).

Conclusions: Intraprocedural percutaneous biopsy of OO at the time of RFA is an effective modality for obtaining histologic diagnosis. The presence of an osteoid matrix, obtaining more than one core sample, and visualization of needle passing through the nidus are predictive of a conclusive biopsy result. Operator experience is valuable and is associated with higher diagnostic yield trending toward significance