Multimodal Management of Metastatic Malignant Meningiomas: The Role of Radiosurgery in Long-Term Local Control

Background: Metastatic meningiomas (MMs) are rare (0.1 of 100 cases). Their treatment requires a multimodal approach, with surgery, radiotherapy, chemotherapy, and radiosurgery, which allows a long-term local control (LC) and an extension of free survival. In this study, the authors performed a review of the literature and reported 2 cases of patients affected by extracranial MMs, with long-term follow-up. Case Description: Case 1: A 48-year-old woman was admitted for resection of an extra-axial falx lesion (meningioma G1). After 2 years, the lesion got a local recurrence, resected with a histologic diagnosis of meningioma G3. During the next 9 years, the patient underwent 5 Gamma Knife radiosurgery (GKRS) procedures for local recurrence. At 56 years, she was readmitted for a surgical local recurrence (histologic definition: anaplastic meningioma G3). At the age of 62, the patient underwent a right lobectomy for a lung mass (histologic diagnosis: anaplastic meningioma G3). After that, multiple lesions at soma L5 and adrenal gland were discovered and then monitored. Case 2: A 48-year-old woman was operated for a lesion involving torcular herophili (meningioma G2). After 3 years, a local recurrence requires GKRS combined with tamoxifen. In the next 7 years, she underwent 5 GKRS procedures for local recurrence. The patient also underwent chemotherapy with octreotide. At the age of 61, she discovered multiple lesions in both lungs, liver, and kidney. A hepatic biopsy showed anaplastic meningioma G3. Also this patient does not suffer from any neurologic or clinical deficits. Conclusions: LC in malignant meningioma is achievable through a multimodal approach; GKRS makes possible LC, but a novel aspect of these lesions is opened to discussion: the metastases. These reports show that multimodal treatment for MMs is an effective approach with good LC and improvement of overall survival. However, a long survival may allow systemic diffusion of the disease, in particular, when sagittal sinus is involved.