Presentation
Pediatric patient with nystagmus and increased calvarial size.
Patient Data
Age: 2 years
Gender: Male
From the case:
Quadrigeminal cistern arachnoid cyst causing hydrocephalus
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MR reveals large supratentorial arachnoid cyst in the quadrigeminal cistern, which was measured 32 x 25 x 20 mm. The cyst is isointense to CSF in all sequences. There is no diffusion restriction. Cyst is compressing the tectum, narrowing the aqueduct, and causing hydrocephalus.
Lateral ventricles and third ventricle were dilated.
Case Discussion
The quadrigeminal cistern is an uncommon location for an arachnoid cyst. Most arachnoid cysts are asymptomatic, but in rare cases large quadrigeminal cistern arachnoid cysts cause narrowing and stretching of the aqueduct causing hydrocephalus.