Denosumab Therapy Related Changes in Giant cell Tumor (Osteoclastoma) of Bone : A New Osteosarcoma Mimicker

Vol 4 | Issue 2 | July-Dec 2018 | Page 4-6 | Pradnya Manglekar, Sujit Joshi, Yogesh Panchwagh.

Authors: Pradnya Manglekar [1], Sujit Joshi [1], Yogesh Panchwagh [1].

[1] Dept. of Pathology Deenanath Mangeshkar Hospital and Research Centre, Pune
[2] Orthopaedic Oncology Clinic, Pune, India.

Address of Correspondence
Dr. Sujit Joshi,
Dept. of Pathology Deenanath Mangeshkar Hospital and Research Centre, Pune


Objectives: Giant cell tumor (Osteoclastoma)of bone is locally aggressive osteolytic tumor. Denosumab–A monoclonal antibody against RANKL is recently being used to treat this tumor. We discuss histopathological changes occurring in giant cell tumor of bone after Denosumab treatment.
Method: A retrospective study of 12 cases from January 2014 to March 2018. All patients included were diagnosed as giant cell tumor (osteoclastoma) of bone on needle or open biopsy. Subsequently these patients received Denosumab therapy followed by surgical resection (extended curettage or wide excision). Histomorphological features after Denosumab therapy were evaluated in these specimens and compared with morphological features of prior biopsy samples.
Results: Needle or open biopsy samples studied prior to receiving Denosumab therapy showed typical morphological features of osteoclastoma i.e. presence of uniformly distributed osteoclastic cells and sheets of mononuclear stromal cells. No atypical mitoses or matrix production noted. Post Denosumab therapy resection specimens showed marked reduction in number of osteoclastic giant cells. There was predominance of mononuclear stromal cells along with abundant, irregular new bone (osteoid) formation with osteoid matrix deposition. Occasional mitotic activity was seen. Few foci of necrosis were noted.
Conclusion: Denosumab treatment causes significant giant cell depletion accompanied by abundant new bone formation separated by cellular stromal proliferation. These features bear very little resemblance to their pre-treatment counterparts and can mimic morphological features of osteosarcoma and other bone forming tumors. Hence, one should be aware of these changes so that a misdiagnosis of osteosarcoma can be avoided.
Keywords: Giant cell tumor (osteoclastoma), Denosumab, RANKL.


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How to Cite this article: Manglekar P, Joshi S, Panchwagh Y. Denosumab Therapy Related Changes in Giant cell Tumor (Osteoclastoma) of Bone : A New Osteosarcoma Mimicker. Journal of Bone and Soft Tissue TumorsJuly-Dec 2018;4(2):4-6.

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