PMC7476695_01
Radiological examination (upper column,[a-e] pre-operative denosumab therapy; lower column, [f-j] post-operative denosumab therapy) showing a reduction in the tumor mass at the retroperitoneum space and intraspinal canal region.
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F1
Initial X-ray and computed tomography (CT) results revealed the presence of an osteolytic lesion involving the L4 vertebra with the abnormal alignment of anterior spondylolisthesis (Fig. 1a and b). Gadolinium-enhanced axial images revealed that the tumor mass expanded into the extravertebral and intraspinal canal spaces (Fig. 1c-e). Follow-up pre-operative X-ray and CT revealed progression of anterior deviation and an increase in vertebral body mineralization (Fig. 1f and g). MRI revealed a decrease in tumor enhancement and a marked reduction in the tumor size in the retroperitoneum space and intraspinal canal region (Fig. 1h-j).
Histological examination, (a and d)immunohistochemical staining of RANK; (b and e) immunohistochemicalstaining of cyclooxygenase-2 (COX-2); (c and f)decrease in the number of multinucleated giant cells and neoplastic mononuclear stromal cells after denosumab therapy. Almost all receptor activator of nuclear factor-kappa (RANK)and COX-2-positive cells were eliminated; however, RANK-positive cells were detected around the woven bone.
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F2
Light microscopy revealed numerous multinucleated giant cells in the background of neoplastic mononuclear stromal cells in pre-operative biopsy samples (Fig. 2a). Immunohistochemical staining revealed RANK-positive mononuclear cells and aggregations of strongly cyclooxygenase-2 (COX-2)-positive mononuclear stromal cells (Fig. 2b and c). The microscopic examination of tissues harvested after denosumab therapy revealed a fibrous matrix with no multinucleated giant cells (Fig. 2d). Immunohistochemistry detected RANK-positive cells around the woven bone, although almost all of the RANK and COX-2-positive cells disappeared (Fig. 2e and f).