To biopsy or not to biopsy: a retrospective review of presumed osteoid osteomas treated by radiofrequency ablation

• Published in: European radiology 2024-09
• Main Authors: Tung, Eric L, Vicentini, Joao R T, Hung, Yin P, Staffa, Steven J, Rosenthal, Daniel I, Chang, Connie Y
• Format: Article
• Language: English
• ISSN: 1432-1084; 1432-1084
• DOI: 10.1007/s00330-024-11088-6

First, to determine the frequency and spectrum of osteoid osteoma (OO)-mimicking lesions among presumed OO referred for radiofrequency ablation (RFA). Second, to compare patient sex and age, lesion location, and rates of primary treatment failure for OO based on histopathology results. A retrospective review was performed of all first-time combined CT-guided biopsy/RFA for presumed OO at a single academic center between January 1990 and August 2023. Lesions were characterized as "biopsy-confirmed OO", "OO-mimicking", or "non-diagnostic" based on pathology results. Treatment failure was defined as residual or recurrent symptoms requiring follow-up surgery or procedural intervention. Variables of interest were compared between pathology groups using Kruskal-Wallis, Fisher's exact, and Wilcoxon rank sum tests. Of 643 included patients (median 18 years old, IQR: 13-24 years, 458 male), there were 445 (69.1%) biopsy-confirmed OO, 184 (28.6%) non-diagnostic lesions, and 15 (2.3%) OO-mimicking lesions. OO-mimicking lesions included chondroblastoma (n = 4), chondroma (n = 3), enchondroma (n = 2), non-ossifying fibroma (n = 2), Brodie's abscess (n = 1), eosinophilic granuloma (n = 1), fibrous dysplasia (n = 1), and unspecified carcinoma (n = 1). OO-mimicking lesions did not show male predominance (46.7% male) like biopsy-proven OO (74.1% male) (p = 0.033). Treatment failure occurred in 24 (5.4%) biopsy-confirmed OO, 8 (4.4%) non-diagnostic lesions, and 2 (13.3%) OO-mimicking lesions without a significant difference by overall biopsy result (p = 0.24) or pairwise group comparison. OO-mimicking pathology is infrequent, typically benign, but potentially malignant. OO-mimicking lesions do not exhibit male predominance. There was no significant difference in RFA treatment failure or lesion location among lesions with imaging appearances suggestive of OO. Question What is the frequency and spectrum of OO-mimicking lesions among presumed OO and what, if any, differences exist between these pathologies? Finding The study cohort included 69.1% OO, 28.6% lesions with non-diagnostic histopathology, and 2.3% OO-mimicking lesions. There was no difference in treatment failure or location among lesions. Clinical relevance Routine biopsy of presumed OO at the time of RFA identifies OO-mimicking lesions, which are rare and likely benign.