[Extracranial metastasis of WHO Grade I benign meningioma: a clinical case and literature review].

Introduction: The majority of meningiomas - benign tumors with an extremely low metastasis tendency. Only singular observations of extracranial metastasis of WHO Grade I benign meningiomas are described in the literature. Despite the intensive study of meningiomas' molecular biology, there are currently no reliable markers indicating the possibility of their metastasis.

Objective: To describe the clinical case report of a patient with meningothelial meningioma of the wings of the sphenoid bone and extracranial metastasis into the pulmonary parenchyma.

Material and methods: Patient with sphenopetroclival meningioma on the left was observed in the clinic. Operations were performed in 2003, 2005 and 2008. In 2009, radiation treatment of the tumor residue in the medial portions of the middle cranial fossa and on the clivus was carried out in a total focal dose of 56.0 Gy. In 2022, multiple lung metastases were detected in presence of a satisfactory condition on CT performed due to suspicion of viral pneumonia.

Results: Histological diagnosis of primary tumor and thoracoscopically resected metastase - WHO Grade I meningothelial meningioma, Ki-67 labeling index amounted to 3%. As of May 2025, the patient's well-being is satisfactory, the Karnofsky index - 80, on the ECOG scale - 1. The primary tumor after radiation treatment in 2009 is stable, metastases in the lungs also have not been progressing since detection in 2022 despite the absence of special treatment.

Conclusion: The presented clinical observation confirms the possibility of distant metastasis of WHO Grade I meningioma and a relatively favorable course of metastatic disease in this case.