Aneurysmal bone cyst and osteoblastoma after neoadjuvant denosumab: histologic spectrum and potential diagnostic pitfalls.

Yin P Hung, Miriam A Bredella, Ingvild V K Lobmaier, Santiago A Lozano-Calderón, Andrew E Rosenberg, G Petur Nielsen

APMIS : acta pathologica, microbiologica, et immunologica Scandinavica 2022 Apr

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The use of denosumab to treat giant cell tumors of bone (GCT) and other giant cell-containing bone tumors has become more common. While the clinicopathologic features of denosumab-treated giant cell tumors of bone have been well-illustrated, descriptions of other denosumab-treated bone tumors are very limited. Surgical pathology files of two institutions and consultation files from two authors were searched for denosumab-treated aneurysmal bone cysts and denosumab-treated osteoblastomas. Clinicopathologic features were reviewed and analyzed. We identified four patients with denosumab-treated bone tumors other than GCT from our surgical pathology and consultation files, including two aneurysmal bone cysts and two osteoblastomas. All were treated with denosumab for 0.5-7.0 (median 4.5) months. Radiologically, denosumab-treated tumors showed decreased size with increased ossification and mineralization on CT and heterogeneous intermediate to hypointense signal on MRI. Histologically, denosumab-treated aneurysmal bone cyst contained thin, elongated, curvilinear, and anastomosing strands of bone with empty lacunae, while denosumab-treated osteoblastoma showed circumscribed nodules of woven bone lined by small osteoblasts. Denosumab-treated aneurysmal bone cyst and osteoblastoma showed treatment-related morphologic changes that can mimic other bone neoplasms. Their recognition requires correlation with the clinical history of denosumab use and radiologic findings. © 2022 Scandinavian Societies for Medical Microbiology and Pathology.

Citation

Yin P Hung, Miriam A Bredella, Ingvild V K Lobmaier, Santiago A Lozano-Calderón, Andrew E Rosenberg, G Petur Nielsen. Aneurysmal bone cyst and osteoblastoma after neoadjuvant denosumab: histologic spectrum and potential diagnostic pitfalls. APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. 2022 Apr;130(4):206-214