Colloid Cyst at the Foramen of Monro Leading to Symptomatic Obstructive Hydrocephalus.

A Caucasian female in her late forties presented to the Emergency Department (ED) with headache, ataxia, and mental status changes. A CT brain demonstrated dilated lateral ventricles with transependymal edema. An MRI of the brain demonstrated marked obstructive hydrocephalus from an obstructing colloid cyst at the level of her Foramen of Monro. The patient was transferred to a tertiary care center for neurosurgical removal of the cyst. Three months later, the patient was doing well and had resumed all activities of daily living without any residual neurological deficits. The goal of this case report is to educate readers on this atypical presentation of hydrocephalus, its symptomatology, and management to allow physicians to be more comfortable in making treatment decisions.