Walsh & Hoyt: Ependymal Cysts

Intracranial cysts lined with ependymal cells are hamartomas that typically become symptomatic in middle-aged adults but that occasionally cause symptoms in childhood or infancy. Seizures and headache are the most common presentation, although diplopia and hemifacial spasm have been reported. Some are located in the supratentorial region, whereas others are located infratentorially. Eggenberger et al. described a 56-year-old woman who developed vertical diplopia and mild difficulties with balance. An examination revealed evidence of an inferior division oculomotor nerve paresis, and neuroimaging revealed a large cystic lesion in the mesencephalon. A stereotactically guided aspiration of the cyst and biopsy of the cyst wall was performed without complication. The aspirate had characteristics of CSF. Pathologic examination of the cyst wall revealed normal neural tissue lined by a single layer of ependymal cells, consistent with an ependymal cyst. Repeat orthoptic assessment 1 day after surgery demonstrated partial resolution of the oculomotor nerve paresis. Van Lindart et al. reported successful treatment of five patients with ependymal cysts by either endoscopic fenestration or endoscope-assisted microsurgical approach.