Description

• Rathke cleft cyst (RCC) is a benign cyst of the sellar region, often an incidental finding on intracranial imaging studies.
• Vast majority are intrasellar in location; rarely, the cyst can be suprasellar.
• Usually asymptomatic, but mass effect can cause headache, visual dysfunction, and/or pituitary endocrinopathies
• Derives from embryologic remnant of Rathke pouch, an outpocketing of the stomodeum (primordial mouth) that ultimately forms the anterior and intermediate pituitary gland lobes
• A simple cyst lined by cuboidal/columnar, ciliated/nonciliated epithelium. The epithelium may contain goblet cells that secrete mucinous material into the cyst and cause the cyst to grow.

Epidemiology

• Female-to-male ratio can be up to 3:1 (perhaps attributable to an increased awareness of endocrinologic dysfunction in females manifesting as menstrual irregularities).
• Age at presentation varies widely, from 4 to 73 years (mean 38 years).
• Highest frequency is in the 5th decade of life; no racial/genetic predilection

Incidence
<1% of all primary intracranial masses

Prevalence
Incidentally found in 13–33% of routine autopsies

Etiology and Pathophysiology

• Derives from embryologic remnants of Rathke pouch
  • Rathke pouch is formed on approximately the 24th day of embryonic life from a diverticulum of the stomodeum (primordial mouth) and is lined by ectodermal epithelium.
  • The pouch extends cranially and is met by the infundibulum, a downgrowth of neuroepithelium from the diencephalon, which ultimately forms the posterior pituitary.
  • Contraction of these two structures causes occlusion at the neck of Rathke pouch at its origin at the buccal–pharyngeal junction; the pouch separates from the oral epithelium and ultimately forms the anterior pituitary lobe from its anterior wall and intermediate pituitary lobe from its posterior wall.
  • The pouch’s lumen normally regresses, but the persistence and enlargement of this pouch creates an RCC.
• Most cysts are microscopic in size and remain asymptomatic.
• Some cysts grow as a result of continued mucus secretion into the cyst by lining epithelium and can become large enough to cause symptoms through mass effect, compressing neighboring structures including the pituitary gland and stalk, optic nerves and chiasm, and hypothalamus.
• An inflammatory response, due to a foreign body reaction against the cystic content, can result in destruction of the surrounding pituitary gland.
• Leakage of a cyst’s mucinous contents/hemorrhage may occur and cause more sudden/episodic symptoms (e.g., severe headache).

Genetics
No genetic inheritance/predisposition identified to date; however, there have been case reports of identical twins with being diagnosed with RCC (1)[C].

Risk Factors

None identified to date

Commonly Associated Conditions

Of RCC, 11% have concurrent pituitary adenoma. Conversely, 0.5–1.7% of pituitary adenomas have concurrent RCC; most frequently occurring with growth hormone (GH) adenomas and prolactinomas