18Fluoro-deoxyglucose positron emission tomography evaluation of benign versus malignant osteochondromas: preliminary observations

OBJECTIVE: To determine the contribution of 18fluoro-deoxyglucose positron emission tomography (18FDG PET) in distinguishing benign from malignant osteochondromas. MATERIALS AND METHODS: From 2000 to 2004, 10 patients (4 females, 6 males, 12 to 64 years old) with osteochondromas were referred for whole body PET by clinicians for metabolic evaluation before planned surgery for pain or cosmesis. Two PET readers and 1 pathologist, blinded to their diagnoses and imaging studies (except for radiographs), correlated results post surgery. The PET average and maximum standard uptake value (SUV) generated by computer for Regions of Interest and correlated with radiographs, were based on axial 3.37 mm thick, 3 x 3 mm pixel images. Since SUVs vary from site to site depending on scanning devices and techniques, a 2.0 maximum cutoff SUV separated benign and malignant osteochondromas based on our standard protocols and specific equipment (Siemens Ecat Exact Knoxville, Tenn) used with our prior oncological studies. RESULTS: Results showed that no definitive statistical conclusions could be drawn due to the small number of patients involved, but they were, nevertheless, deemed promising. CONCLUSIONS: The 18FDG whole body PET aided the identification of malignant osteochondromas, their local recurrence and metastases by both displaying and quantifying their metabolic activity. Although the current study is limited by a small cohort, which precludes statistical analysis, additional experience with PET analysis of osteochondromas may further support its value as a physiological parameter supplementing anatomically based imaging modalities most often used for their evaluation.