Presentation
Vague headaches.
Patient Data
Selected images from a contrast enhanced MRI demonstrate an incidental 12mm cystic lesion in the region of the pineal gland. The tectal plate is somewhat distorted (best seen on sagittal T1 image) but there is no evidence of obstructive hydrocephalus.
The cyst does not have any solid component and has fluid signal which does not however fully attenuate on FLAIR. There is no restricted diffusion on DWI/ADC.
On the coronal post gad image the internal cerebral veins can be seen elevated and splayed.
Figure 1: the pineal cyst (blue arrows) compresses the tectal plate (orange arrow).
Figure 2: splayed internal cerebral veins (blue arrows) should not be mistaken for nodular enhancement.
Case Discussion
This case demonstrates typical appearances of an incidental pineal cyst. These are found in up to 5% of all brain MRIs, and as such pose a problem in deciding which should be followed up.
In general large size (>10-12mm) or any atypical features warrant followup to ensure that they do not represent a cystic pineal neoplasm (e.g. pineocytoma).