A Rathke's cleft cyst is a benign growth on the pituitary gland in the brain, specifically a mucin-filledAbdelzaher, E. Rathke cleft cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cnstumorrathkecyst.html. Accessed May 26th, 2018. cyst in the posterior portion of the anterior pituitary gland. It occurs when the Rathke's pouch does not develop properly and ranges in size from 2 to 40 mm in diameter.
