Microcystic meningioma without enhancement on neuroimaging--case report

A 63-year-old female presented with an unusual case of microcystic meningioma manifesting as a 4-year history of unsteady gait, dysarthria, and hearing loss. Computed tomography disclosed a large hypodense mass in the right cerebellopontine angle, clivus, and middle fossa, with slight contrast enhancement. T1-weighted magnetic resonance images demonstrated the lesion as a hypointense mass, which was little enhanced gadolinium-diethylenetriaminepenta-acetic acid. Right carotid angiography revealed blood supply from the external carotid artery, but no tumor staining. The extracerebral tumor was subtotally removed. The histological diagnosis was microcystic meningioma. Light microscopy revealed abundant microcystic throughout the tumor tissue, and electron microscopy disclosed that the microcysts were mostly located in the extracellular spaces and only a few in the cytoplasm. Microcystic meningioma without enhancement is rare and should be differentiated from low-grade astrocytoma, epidermoid, or other non-enhanced tumor.