Pineal Cyst

Pineal cyst is a frequently-discovered incidental finding. There are several neoplasms which may arise in the pineal, such as germ cell tumours (germinoma, embryonal carcinoma, choriocarcinoma, teratoma), pineocytoma, pineoblastoma, and metastases. These tumours may contain cystic elements, and several are highly malignant. As the majority of pineal cysts are benign, it is often difficult to know the appropriate management of an incidental finding.
A study1 of 32 patients with pineal cyst, followed up from 6 months to 9 years, found cyst enlargement in only 3 patients, 75% remaining the same, and the rest shrinking. The authors conclude that cysts with typical features may be followed up clinically, rather than with imaging.
The typical pineal cyst is smooth, well-rounded, and follows CSF signal characteristics. High protein content or haemorrhage may give altered signal. Atypical features include thick or nodular walls, septation, a soft-tissue component, or non-peripheral contrast enhancement, and should prompt further investigation, including testing for hormones from germ cell tumours.
Many clinicians opt to follow up an incidentally discovered pineal cyst with interval imaging.
References:
1. Barboriak, D P. Lee, L. Provenzale, J M. Serial MR imaging of pineal cysts: implications for natural history and follow-up. American Journal of Roentgenology. 176(3):737-43, 2001 Mar.
2. BrighamRAD
Credit: Dr Laughlin Dawes
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