Cyberknife stereotactic radiosurgery and denosumab for giant cell tumour of the skull base: Case report

Treatment of Clival Giant Cell Tumor: A Case Report and Literature Review

Giant cell tumors (GCTs) are locally aggressive primary bone tumors of osteoclast-like cells. Most GCTs occur within the long bones, and primary GCTs involving the clivus are extremely rare. We present the case of an 18-year-old boy with binocular horizontal diplopia with an insidious onset who was found to have a hypointense enhancing mass involving the clivus and left side dorsum sellae on magnetic resonance images. The tumor was completely resected via an endoscopic endonasal transclival approach, and histopathologic examination via immunohistochemistry indicated a GCT. The patient's left abducens nerve palsy improved slightly after surgery. Because of the rarity of GCTs, there is no consensus about the definitive treatment protocol. However, we suggest that gross total resection is the treatment of choice, and denosumab plays a critical role in patients with subtotal resection.

Unresectable Clival Giant Cell Tumor, Tumor Control With Denosumab After Relapse: A Case Report and Systematic Review of the Literature

Giant cell tumors (GCTs) of the skull base are rare entities. Although considered histologically benign, GCTs are locally aggressive with a high rate of local recurrence. The present case describes a 14-year-old girl with a clival GCT who underwent long-term therapy with denosumab after local relapse. To our knowledge, it is the second case described with a follow-up term >2 years from the start of denosumab and who did not receive any other adjuvant treatment besides denosumab. The patient achieved a local control of the disease. According to the few available data, radical excision with adjuvant therapy helps in long-term control in uncommon sites, such as the skull. However, the definitive treatment is still controversial because of their rarity and few follow-up data. The present case highlights the benefit of denosumab and its safety as long-term therapy and contributes to the existing literature with analysis and evaluation of the management strategies and prognosis.

Preoperative Cytoreduction of Clival Giant Cell Tumor: An Effective Replication of the Systemic Modality in the Skull Base

BACKGROUND

Giant cell tumors (GCTs) are benign tumors with a predilection for the epimetaphyseal region of the long bones. GCTs involving the skull base are rare, and only a few available cases have been reported. Surgical gross total resection is the recommended method of treatment for GCTs. In the case of skull base tumors, it is very difficult to achieve such a result by direct surgical resection alone without any morbidities. Denosumab is a fully humanized monoclonal anti-receptor activator of nuclear factor-κB ligand antibody that has been recently approved by the Food and Drug Administration for the treatment of GCTs that are surgically unresectable, metastatic, and have a high risk of progression and recurrence. Denosumab has been used in many cases involving the long bones. However, in cases of skull base GCTs, only a limited number of cases have been reported. In addition, in such cases, it was used as postoperative chemotherapy owing to subtotal resection.

CASE DESCRIPTION

For the present patient, we adopted a unique approach in which denosumab was administered as neoadjuvant chemotherapy to reduce the size of the tumor to a resectable level. Subsequently, surgical resection was performed with good functional and histopathological outcomes.

CONCLUSIONS

Our findings emphasize the use of denosumab as a neoadjuvant treatment routinely for all cases of skull base GCTs to achieve safe and complete excision of the tumor.