Giant cell tumors of bone (GCTB) are generally classified as indolent neoplasms but are notable for local aggressiveness. Metastatic spread is uncommon and, when it occurs, most frequently involves the lungs. Central nervous system involvement is exceedingly rare. The authors report that, prior to this publication, only two other cases of secondary central nervous system lesions from GCTB had been described in the literature, making this the third documented occurrence of such metastasis.
Clinical recognition of atypical metastatic patterns for GCTB is important because rare manifestations can present diagnostic and therapeutic challenges distinct from the more typical pulmonary spread.
The report describes a 39-year-old patient without significant past medical history who was diagnosed with a GCTB of the left distal femur. Initial management included preoperative denosumab therapy followed by surgical resection. The orthopedic procedure included extensive resection and reconstruction with a large prosthesis. The immediate postoperative course and details of resection margins were not specified in the abstract.
The use of preoperative denosumab in this case aligns with contemporary strategies to reduce tumor burden and facilitate limb-sparing surgery in selected patients with GCTB; the abstract does not provide further detail on dosing, duration, or treatment response beyond noting its use.
Fifteen months after the index surgery the patient developed neurological symptoms consisting of tremors and a partial seizure. Neuroimaging identified a right parietal intracranial lesion. Surgical excision of the lesion was performed and histopathological analysis confirmed the intracranial mass as a metastatic deposit originating from the patient’s previously treated GCTB of bone.
Histological confirmation establishes this lesion as a secondary brain metastasis rather than a de novo primary brain neoplasm. The abstract specifies that magnetic resonance imaging (MRI) was used for postoperative monitoring, consistent with standard neuro-oncology follow-up modalities.
Management of the intracranial metastasis in this patient consisted of surgical removal of the right parietal lesion. Following excision, the treating team elected close clinical and radiological surveillance with brain MRI rather than administering adjuvant radiotherapy. The abstract does not indicate use of systemic therapy directed at the metastatic disease after neurosurgery.
At the time the report was written, the patient was reported to be in clinical and radiological remission. Detailed timelines for follow-up imaging frequency and neurologic status measures were not reported in the abstract.
The authors place this case alongside two prior published reports of central nervous system involvement by GCTB: one described an intramedullary thoracic lesion and another described bilateral parietal lesions. The limited number of reported cases underscores the rarity of central nervous system metastases from GCTB and limits any firm conclusions about optimal surveillance or treatment strategies for such presentations.
Because only isolated case reports exist, aggregated evidence is insufficient to support routine screening of the brain for metastasis in all patients with GCTB. Instead, the literature to date suggests that detection of CNS involvement will typically be symptom-driven and managed on a case-by-case basis.
From this report the authors draw practical recommendations grounded in the current evidence base:
Maintain prolonged clinical and radiological follow-up for patients with GCTB, given the tumor’s potential for uncommon metastatic behavior.
Adopt an individualized, multidisciplinary approach to follow-up and treatment decisions rather than applying a universal protocol; this includes collaboration between orthopedic oncology, medical oncology, neuro-oncology, neurosurgery, and radiology when atypical metastases are suspected or confirmed.
Routine brain imaging is not justified solely on the basis of this limited case series; instead, brain imaging should be driven by clinical signs or symptoms suggestive of neurological involvement.
These points reflect the authors’ cautionary stance that rare events should prompt vigilance and tailored management but do not yet mandate changes to standard surveillance algorithms.
This case documents the third reported instance of histologically confirmed brain metastasis arising from a GCTB. The lesion presented with focal neurological symptoms 15 months after primary surgery and was managed successfully with surgical excision and MRI surveillance, with the patient in remission at last report. The case highlights the importance of extended follow-up and multidisciplinary decision making for GCTB, while recognizing that the rarity of central nervous system spread does not support routine brain imaging in all patients. Additional case reports and series would be required to develop evidence-based recommendations for surveillance or adjuvant management of CNS metastases from GCTB.