PMC9343706_01
Response of target lesion (located in the sacrum) to denosumab in a metastatic giant cell tumor of the bone (GCTB). Left panel's image is a CT scan showing a sacral lesion at baseline, and, on the right panel, a CT scan after 3 months of denosumab treatment showing a reduction in tumor size (partial response according to RECIST 1.1).
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Subsequent systemic staging highlighted a 5-cm large sacral primary ( Figure 1 , left panel), multiple bone (D9-11, L3, L5, right hemi-sacrum, and right femur) metastases and one single pulmonary metastasis in the superior lobe of the left lung. Given the diagnosis and the disease extent, in November 2009, she was started with denosumab (120 mg subcutaneously, once per month, following the loading dose of 120 mg day 1-8-15), obtaining a reduction in tumor size and resolution of all GCTB-related symptoms ( Figure 1 , right panel).
Plain X-ray showing complete, displaced femoral diaphyseal fracture (left panel), reported as an atypical femur fracture (AFF). Patient was treated with open reduction and intramedullary nailing, but bone healing was delayed (plain X-ray after 5 months from surgery, central image). Bony callus eventually fully consolidated after 13 months (right panel).
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The fracture carried the typical clinical and radiological features of a complete displaced AFF ( Figure 2 , left panel), which was related to denosumab. The patient was treated with open reduction and intramedullary nailing, along with calcium and vitamin D daily supplements, to accelerate fracture healing ( Figure 2 , right panel).
After 14 months from denosumab discontinuation due to AFF, progressive disease was documented (new lesions in right iliac wing and L5 soma, left panel) and denosumab restarted. On the right panel, a CT scan obtained 3 months later shows stabilization of disease (stable disease according to RECIST 1.1).
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GCTB remained stable for 14 months after denosumab discontinuation, when a new CT scan showed progressive disease by RECIST, marked by the appearance of two new lesions in the right iliac wing and in L5 soma ( Figure 3 , left panel). At the first re-assessment, 3 months later, a new tumor stabilization was documented and confirmed at 1 year, with no evidence of AFF relapse or additional serious adverse events reported ( Figure 3 , right panel).