EXO1 homozygous deletion suppresses the hydroxyurea sensitivity in anaplastic meningioma with extracranial metastases

Background: Anaplastic meningioma is exceedingly rare, and its clinicopathological features are distinctive. Distant meningioma metastases have previously been reported to be very rare. The most common site of metastasis is the lung, which accounts for 61% of all meningioma metastases. The standard therapy for meningiomas is total resection and/or radiation therapy. Case Report: A 71-year-old man was admitted with headache and left hemiparesis. Magnetic resonance imaging (MRI) revealed mass lesions at the right frontal convexity and left occipital lobe. Following surgery, pathological examinations demonstrated an anaplastic meningioma. At 3 months after the operation and radiation therapy, lung tumor was removed. The pathological findings for the lung tumor resembled those of the brain tumor. A diagnosis of metastatic lung tumor from anaplastic meningioma was made. At 2 months after the lung surgery, MRI disclosed focal recurrence in the frontal convexity area and progression into the cavernous sinus. Abdominal CT detected a new metastatic lesion in the patient’s liver. He underwent adjuvant reirradiation consisting of whole brain radiotherapy. In addition, he received chemotherapy using angiogenesis receptor (bevacizumab). Chemotherapy with hydroxyurea was initiated after 2 courses of the bevacizumab chemotherapy, because his hepatic lesion had become more aggressive. The intracranial mass was reduced by 50% at 8 weeks after initiation of the hydroxyurea chemotherapy. However, there was no significant effect on the liver and lung metastases. Analysis and Conclusion: Extracranial metastases have been estimated to occur in only 0.1% of all meningiomas and most often in association with anaplastic meningiomas. While total resection and/ or radiation treatment provide the standard therapy for meningiomas, use of chemotherapy against meningiomas has been limited to distant metastases or based on out of surgical criteria. Several reports have demonstrated that hydroxyurea provides on effective chemotherapy for meningiomas including grade I cases. Hydroxyurea halts meningioma cell growth through arrest of the S-phase of the cell cycle, thus inducing apoptosis. Our analysis revealed EXO1 homozygous deletion at exons 8 and 10 in the patient’s extracranial metastatic meningioma. The findings suggested that EXO1 homozygous deletion may be associated with suppression of hydroxyurea sensitivity in anaplastic meningiomas. Hydroxyurea should be a justified therapeutic adaptation in cases of anaplastic meningioma without EOX1 homozygous deletion.