髄膜腫の注意すべきmimickersと鑑別

Imaging Features and Differential Diagnosis of Meningiomas and Their Mimics

Point

・髄膜腫は日常遭遇する頻度の高い腫瘍であるが，多種多彩な画像所見を呈するため，他の疾患との鑑別を要することがある．

・腫瘤性病変の鑑別としては，神経鞘腫，孤立性線維性腫瘍，硬膜転移，組織球症などがある．

・硬膜肥厚を呈する病態の鑑別としては，肥厚性硬膜炎（特発性，ANCA関連疾患など），真菌感染，IgG4関連疾患などがある．

　Meningiomas are the most common brain tumors, often in the form of extra-axial masses adhering to the dura mater. Although there are typical imaging findings, meningiomas have a wide variety of imaging findings, owing to their different histological subtypes. Thus, it can be difficult to differentiate meningiomas from other diseases that present with similar imaging findings. This section outlines mimickers for monitoring meningiomas that present with imaging findings similar to those of meningiomas. Diseases that form masses and require differentiation from meningiomas include schwannomas, solitary fibrous tumors, dural metastases, and histiocytosis. Diseases that primarily present as dural thickening and require differentiation from meningiomas include hypertrophic duralitis, fungal infections, and IG4-related diseases. Notably, in addition to the various pathologies that can mimic meningiomas, such as those listed above, there are also cases in which the diagnosis of meningioma is difficult because of additional modifications, such as metastasis or meningioma infarction.