From the archives of the AFIP - Imaging of giant cell tumor and giant cellreparative granuloma of bone: Radiologic-pathologic correlation

The radiologic features of giant cell tumor (GCT) and giant cell reparative granuloma (GCRG) of bone often strongly suggest the diagnosis and reflect their pathologic appearance. At radiography, GCT often demonstrates a metae piphyseal location with extension to subchondral bone. GCRG has a similar a ppearance but most commonly affects the mandible, maxilla, hands, or feet. Computed tomography and magnetic resonance (MR) imaging are helpful in stag ing lesions, particularly in delineating soft-tissue extension. Cystic (sec ondary aneurysmal bone cyst) components are reported in 14% of GCTs. Howeve r, biopsy must be directed at the solid regions, which harbor diagnostic ti ssue. These solid components demonstrate low to intermediate signal intensi ty at T2-weighted MR imaging a feature that can be, helpful in diagnosis. M ultiple GCTs, although rare, do occur and may be associated with Paget dise ase. Malignant GCT accounts for 5%-10% of all GCTs and is usually secondary to previous irradiation of benign GCT. Treatment of GCT usually consists o f surgical resection. Recurrence is seen in 2%-25% of cases and imaging is vital for early detection. Recognition of the spectrum of radiologic appear ances of GCT and GCRG is important in allowing prospective diagnosis, guidi ng therapy, and facilitating early detection of recurrence.