髄膜腫の疫学と自然歴・増大リスク

Epidemiology, Natural History, and Growth Risk of Meningiomas

Point

・髄膜腫は最も頻度が高い原発性脳腫瘍であり，近年無症候性病変の指摘が増加しているため，治療マネジメントの重要性が増している．

・多くの無症候性病変に対しては慎重な経過観察が第一選択であるが，増大しやすい髄膜腫の特徴を把握することが必要である．

・増大速度や増大パターンなどを確認し，治療介入のタイミングや必要性を考慮することが重要である．

　Meningiomas are the most common primary intracranial tumors. As the number of incidentally discovered meningiomas has increased with the widespread access and use of neuroimaging, treatment strategies for meningiomas have become more important. Close observation is the first choice for asymptomatic lesions; however, the natural history of meningiomas remains unclear. It is necessary to recognize the characteristics of meningiomas that are likely to grow, such as high signal intensity on MRI T2WI. It is also important to examine the growth rates and patterns using multiple neuroimaging examinations during the follow-up period. The authors suggested a relationship between the various observed growth patterns and the length of the follow-up period based on the assumed development of tumor volume. Less than 10% of patients with asymptomatic meningiomas develop symptoms and require treatment. However, it remains unclear which lesions become symptomatic, and further studies are required. Lesions with a sustained growth pattern undergo preventive treatment interventions, but the need for and appropriate timing of these interventions are continuously under debate. Further studies will help elucidate the natural history of meningiomas.