An isolated primary Rathke's cleft cyst in the cerebellopontine angle

Rathke's cleft cysts (RCCs) are benign cysts typically located in the sellar or suprasellar region; ectopic isolated lesions are extremely rare. The authors describe the case of a 25-year-old man with a giant symptomatic RCC arising primarily at the cerebellopontine angle (CPA), only the second case reported thus far. The patient presented with a 2-year history of right hearing impairment and tinnitus accompanied by vertigo and headache and a 2-week history of right facial numbness. Subsequently, he underwent total cyst removal via retrosigmoid craniotomy with a good recovery. He experienced no recurrence during a 64-month follow-up period. The possible pathogenesis, differential diagnosis, and surgical treatment of such cysts are discussed in this article. Isolated ectopic RCCs can arise from the ectopic migration of Rathke's pouch cells during the embryonic period. It is still difficult to distinguish ectopic RCCs from other cystic lesions of the CPA given the lack of specific imaging features. Aggressive resection of the cyst wall is not recommended, except when lesions do not closely adhere to adjacent structures.