pineal cyst
Benign cystic lesion of the pineal gland, typically asymptomatic and following CSF signal characteristics.
Full Definition
Pineal cysts are benign, fluid-filled lesions arising within the pineal gland that are commonly discovered incidentally on brain imaging. These cysts follow cerebrospinal fluid signal characteristics on all MRI sequences and typically measure less than 2cm in diameter. They may have thin walls that can demonstrate minimal enhancement, and occasionally contain proteinaceous material causing slightly different signal characteristics. Most pineal cysts are asymptomatic, but large lesions may compress the aqueduct of Sylvius causing hydrocephalus or affect the superior colliculus leading to Parinaud's syndrome. They should be distinguished from pineal region tumors such as pineocytoma or germinoma.
Usage
Usage note: Specify size and note any mass effect on surrounding structures.
In Context
- "A 1.2cm pineal cyst was noted incidentally on the sagittal T1-weighted images." — Routine brain MRI
- "The large pineal cyst was causing mild aqueductal compression." — Hydrocephalus workup