We provide an overview of imaging, histopathology, genetics, and multidisciplinary treatment of giant cell tumor of bone (GCTB), an intermediate, locally aggressive but rarely metastasizing tumor. Overexpression of receptor activator of nuclear factor kB ligand (RANKL) by mononuclear neoplastic stromal cells promotes recruitment of numerous reactive multinucleated giant cells. Conventional radiographs show a typical eccentric lytic lesion, mostly located in the meta-epiphyseal area of long bones. GCTB may also arise in the axial skeleton and very occasionally in the small bones of hands and feet. Magnetic resonance imaging is necessary to evaluate the extent of GCTB within bone and surrounding soft tissues to plan a surgical approach. Curettage with local adjuvants is the preferred treatment. Recurrence rates after curettage with phenol and polymethylmethacrylate (PMMA; 8%-27%) or cryosurgery and PMMA (0%-20%) are comparable. Resection is indicated when joint salvage is not feasible (e.g., intraarticular fracture with soft tissue component). Denosumab (RANKL inhibitor) blocks and bisphosphonates inhibit GCTBderived osteoclast resorption. With bisphosphonates, stabilization of local and metastatic disease has been reported, although level of evidence was low. Denosumab has been studied to a larger extent and seems to be effective in facilitating intralesional surgery after therapy. Denosumab was recently registered for unresectable disease. Moderate-dose radiotherapy (40-55 Gy) is restricted to rare cases in which surgery would lead to unacceptable morbidity and RANKL inhibitors are contraindicated or unavailable. The Oncologist 2014;19:550-561 Implications for Practice: Giant cell tumor of bone (GCTB) is an intermediate, locally aggressive, primary bone tumor. Ideally, all patients should be treated with intralesional excision with local adjuvant treatment (e.g., phenol, liquid nitrogen, polymethylmethacrylate), achieving joint salvage and optimal functional outcome. In patients with high-risk GCTB or in rare cases of metastatic disease, systemic targeted therapy with the receptor activator of nuclear factor kB ligand inhibitor denosumab is highly effective and may create an operable situation. Moderate-dose radiotherapy is indicated only for rare cases of unresectable, residual or recurrent GCTB in which denosumab is contraindicated or unavailable for preoperative treatment and when surgery would lead to unacceptable morbidity.

Purpose: To explore the potential of perfusion-corrected diffusion-weighted magnetic resonance imaging (MRI) in characterizing soft-tissue tumors. Materials and Methods:Diffusion-weighted MRI was performed in 23 histologically proven soft-tissue masses using a diffusion-weighted spin-echo sequence with diffusion gradient strengths yielding five b-values (0 -701 seconds/ mm 2 ). True diffusion coefficients and perfusion fractions were estimated and compared with apparent diffusion coefficients (ADCs).Results: ADC values of all tumors, subcutaneous fat, and muscle were significantly higher than true diffusion coefficients, indicating a contribution of perfusion to the ADC. True diffusion coefficients of malignant tumors (1.08 ϫ 10 -3 mm 2 /second) were significantly lower than those of benign masses (1.71 ϫ 10 -3 mm 2 /second), whereas ADC values between these groups were not significantly different. Conclusion:Perfusion-corrected diffusion-weighted MRI has potential in differentiating benign from malignant softtissue masses.

We provide a detailed description of the MRI in sIBM and show a distinct pattern of muscle involvement. Relatively severe affliction of the medial compartment of the gastrocnemius, combined with relative sparing of the rectus femoris or involvement of the FDP can be indicative of sIBM. MRI can contribute to the diagnosis in selected patients with clear clinical suspicion, but lacking the mandatory set of muscle biopsy features.

This cohort of patients with detailed follow-up data enabled us to identify important risk factors determining survival in OS patients with pulmonary metastases. We demonstrate that after repeated metastasectomies, a subset of patients can be cured.

Conventional and dynamic contrast-enhanced MR parameters can be used in combination to categorize vascular malformations. Dynamic contrast-enhanced MR imaging allows diagnosis of venous malformations with high specificity.