Volume 130, Issue 4 pp. 206-214
Original Article

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

Yin P. Hung

Yin P. Hung

Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA

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Miriam A. Bredella

Miriam A. Bredella

Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA

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Ingvild V. K. Lobmaier

Ingvild V. K. Lobmaier

Department of Pathology, Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway

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Santiago A. Lozano-Calderón

Santiago A. Lozano-Calderón

Department of Orthopedics, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA

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Andrew E. Rosenberg

Andrew E. Rosenberg

Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA

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G. Petur Nielsen

Corresponding Author

G. Petur Nielsen

Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA

G. Petur Nielsen, Department of Pathology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA. e-mail: [email protected]

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First published: 03 February 2022
Citations: 2

Abstract

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.

CONFLICT OF INTEREST

YPH, AER, and GPN received royalties from Elsevier for authoring pathology book chapters, which are unrelated to this study.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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