Successful Intravascular Correction of Intratumoral Pseudoaneurysm by Erosion of the Aorta in a Patient with Thoracic Giant Cell Tumor of Bone Responding to Denosumab

Abstract

Giant cell tumor of bone (GCT) is a rare, locally aggressive neoplasm characterized by the presence of giant cells with osteoclast activity. Its biology involves the overexpression of the Receptor Activator of Nuclear Factor kB Ligand (RANKL) by osteoclast-like giant cells and tumor stromal cells, which has been shown to be an actionable target in this disease. In cases amenable to surgical resection, very few therapeutic options were available until the recent demonstration of significant activity of the anti-RANK-ligand monoclonal antibody denosumab. Here we present a case of a patient with advanced GCT arising in the spine, recurring after multiple resections and embolization. Following initiation of denosumab, which resulted in unequivocal clinical improvement, computed tomography of the chest done for reassessment purposes revealed an intratumoral pseudoaneurysm by erosion of the aorta, further corrected by endovascular approach and stent placement. Patient had an unremarkable recovery from the procedure and continued benefit from therapy with denosumab and remains on treatment 24 months after the first dose.

Figure 1

Hematoxylin and eosin-stained tumor tissue depicting osteoclast-like giant cells.

Figure 2

Baseline (pretreatment) MRI findings on T2-weighted (a) and postgadolinium T1-weighted (b) images showing a mass arising from the vertebral body (wide arrow), with a heterogeneous soft tissue component with solid (narrow arrow) and cystic areas (dashed arrow).

Figure 3

Postcontrast CT on soft reconstruction filter (a) and hard reconstruction filter (b), showing a lytic bone lesion arising from the vertebral body (wide arrow) with a large soft tissue component (narrow arrow).

Figure 4

Postcontrast/arterial phase (a) and oblique reformatting (b) showing a pseudoaneurysm arising from the thoracic aorta and more prominent areas of calcification consistent with response to treatment.

Figure 5

Postcontrast/arterial phase (a) and oblique reformatting (b) after successful placement of aortic endovascular stent graft and repair of the pseudoaneurysm.

Figure 6

Long-term follow-up CT after continued treatment with denosumab showing more prominent calcification (wide arrow) and reduction of the soft tissue component (narrow arrow). The aortic stent is seen, without extravasation of contrast (dashed arrow).