Pituitary Cysts

Pituitry cyst. Courtesy of A. Jefferies

Act as space-occupying lesions producing a pathology of the pituitary. May arise from two developmental structures:

• The cranio-pharyngeal ducts which are the route by which the developing anterior pituitary ascends from the pharynx. The craniopharyngeal ducts are the neck of Rathke's pouch which, during development, narrows, closes and separates the vesicle of Rathke's pouch from the oral cavity. These cysts have columnar ciliated epithelial cells lining the cyst and contain mucin.
  The craniopharyngeal ducts may also become neoplastic; Craniopharyngioma. These tumours contain single or multiple cysts.
• Rathke's Pouch which may fail to differentiate and becomes cystic.