Intracranial anaplastic hemangiopericytoma presenting with simultaneous extra-cranial metastases: A case report and review of the literature

Background: Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare mesenchymal tumor with a propensity to recur and metastasize extracranially years after treatment. Accordingly, there are no reported cases of a patient presenting with a simultaneous intracranial primary and extracranial metastases. We present the case of a patient presenting with an intracranial SFT/HPC and simultaneous liver metastases and propose a treatment paradigm. Case Description: A 74-year-old male smoker presented with confusion. An MRI of the brain revealed a heterogeneously enhancing left frontal extra-axial mass. Systemic workup revealed multiple small liver lesions concerning for metastases. The patient underwent gross total resection (GTR) of the intracranial lesion with adjuvant CyberKnife stereotactic radiotherapy to the resection cavity. Pathology was consistent with a WHO Grade III SFT/HPC (previously known as anaplastic HPC). The liver lesions were biopsied and confirmed to be metastases. They were subsequently treated with stereotactic body radiation therapy, temozolomide, and bevacizumab. Eighteen months postoperatively, the patient is alive with no evidence of intracranial malignancy and regression of the hepatic lesions. Conclusion: Several studies support GTR and adjuvant radiotherapy to treat intracranial SFT/HPC. The role of adjuvant chemotherapy is less clear. Metastatic disease is typically detected several years after the initial diagnosis, and there is no consensus regarding the optimal treatment strategy. We propose that the rare presentation of intracranial SFT/HPC with simultaneous extracranial metastases should be treated in a multidisciplinary fashion with surgical resection, adjuvant radiotherapy, and chemotherapy.