Pineal gland cyst

A pineal gland cyst is a usually benign (non-malignant) cyst in the pineal gland, a small endocrine gland in the brain. Historically, these fluid-filled bodies appeared on 1-4% of magnetic resonance imaging (MRI) brain scans, but were more frequent at death, seen in 21-41% of autopsies. A 2007 study by Pua et al. found a frequency of 23% in brain scans (with a mean diameter of 4.3 mm).