Purpose: To evaluate the frequency, morphology and clinical long term evolution of pineal cysts depicted on MRI.
Patients and methods: one thousand eight hundred and forty four (1 532 women and 126 men) MRI examinations were retrospectively reviewed. Coronal and sagittal spin echo T1 weighted sequences without and with gadolinium injection were performed, completed with spin echo T2 weighted images when a cystic sellar lesion was suspected. A pineal cyst was diagnosed as a rounded well defined lesion, with fluid signal in an enlarged pineal gland. Follow-up examinations were performed to evaluate the efficacy of the treatment of the sellar lesion.
Results: Twenty one epiphyseal cysts (1.27%) were diagnosed in 20 women (1.31%) and one man (0.79%). Their size was 1,2 +/- 0,4 cm (0,3 to 2 cm). They were asymptomatic. In 10 patients, follow-up MRI examinations did not show any change in size. During the clinical follow-up, these twenty-one patients remained asymptomatic (6 months to 5 years).
Conclusion: The incidental detection of a pineal cyst at MRI is not exceptional. This lesion's pattern appears characteristic and their reputation of benignity is confirmed in our study.