Presentation
Severe headaches for 4 months. Features of raised intracranial pressure
Patient Data
A large cyst obstructing the foramen of Monro with associated trilateral hydrocephalus and transependymal edema. The cyst is hyperintense on FLAIR, T2 and T1W imaging with a thin T2W hypointense rim. Bifrontal burr holes noted.
A well delineated hyperdense non-enhancing cyst centered over the foramen of Monro with severe hydrocephalus and subependymal hypoattenuation. Associated generalized cerebral edema with effacement of surface sulci at the vertex. Normal fourth ventricle and no downward herniation. The imaging features are classic for a colloidal cyst.
Case Discussion
The patient had surgery with histopathological confirmation of a colloidal cyst. The imaging features are consistent with a colloidal cyst. Other differentials include masses arising from the foramen Monro. Patients with colloidal cysts of the third ventricle may present with sudden death due to obstruction of CSF flow at the level of the foramen of Monro.