Rathke's cleft cyst
A Rathke's cleft cyst is a benign lesion near the pituitary gland in the brain. During development of the pituitary gland the Rathke’s pouch forms. Then the anterior pouch wall thickens to form the anterior pituitary lobe. A Rathke's cleft cyst is thought to come from the remains of the Rathke’s pouch. The pituitary gland sits in a little saddle shaped spot, known as the “sella turcica” at the base of the skull. This literally means “Turkish saddle,” as it is shaped as such. A Rathke’s cleft cyst is also located in this sella turcica as well; it is “intrasellar.” The remains of the pouch form a thin-walled cyst filled with a substance that resembles motor oil.
It is mostly asymptomatic unless it becomes large and presses on the surrounding structures. It can press on the pituitary gland affecting the hormone production. It can also compress the optic nerves resulting in some visual disturbances, such as tunnel vision or decreased peripheral vision.
A CT or MRI scan are used to visualize the lesion. Because it is so close to the pituitary gland it is often hard to diagnose just from a CT or MRI scan. If the Rathke's cleft cyst is symptomatic or suspicious for something else, treatment is often a partial excision and drainage of the cyst with biopsy. This can be done in the same manner that a pituitary tumor is removed: by a transsphenoidal resection. This is where the cyst or lesion is accessed through the nose, and removed. Depending on the location and the individual anatomy, it may also be accessed through a craniotomy.
Lindsey Parker PA-C and Justin F. Fraser MD