NeuroradiologyPineal cyst
usually an incidental finding, calculated as being present in 40% of routine autopsies. But occasionally, pineal cysts can bleed internally or be so large that they may be a cause of aqueductal compression with secondary hydrocephalus and gaze disorders. The role of the neuroradiologist in this case is to distinguish the pineal
cyst from a pineal
neoplasm and to recognize it as a
benign and probably noncontributory factor to the patient's clinical symptoms. The differential diagnosis with tumours of the pineal region is made by noting carefully the
cystic round and smoothly marginated nature of the
lesion. The signal intensity of the
cyst may be misleading as, due to high protein content or old haemorrhages, it may differ from CSF most frequently displaying higher signal on T1-weighted images (
Fig.1). Contrast injection is therefore helpful since, unlike most tumours of the pineal region, the
cyst will display only peripheral enhancement.
FS
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a. Midline sagittal T1-weighted MR image. The pineal is markedly enlarged and almost completely cystic. The signal is hypointense, close to that of CSF. The superior colliculi are slightly compressed.
b, c. Axial proton density- and T2-weighed images showing signal of the cystic pineal to be higher than that of CSF.
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Pineal cyst, Fig.1 (a) | | Pineal cyst, Fig.1 (b) | | Pineal cyst, Fig.1 (c) |