Persisting Embryonal Infundibular Recess (PEIR): Two Case Reports and Systematic Literature Review.

Context: The persisting embryonal infundibular recess (PEIR) is a rare anomaly of the floor of the third ventricle with a debated pathogenesis. It can be a cause of misdiagnosis in the case of cystic lesions of the sellar and suprasellar area. Objective: To describe two recently evaluated cases and provide a systematic literature review. Evidence Acquisition and Case Descriptions: PEIR has been previously reported in six adult patients. Because in some cases it was associated with hydrocephalus and/or empty sella, a possible role of altered intracranial pressure in PEIR formation has been postulated. We evaluated two female patients, aged 34 and 50 years, referred to the Pituitary Surgery Clinic of the University of Brescia with the diagnosis of a sellar cyst and craniopharyngioma, respectively. Endocrine screening and visual field testing were normal. No signs of hydrocephalus or empty sella, as well as other indirect signs of intracranial hypertension, were visible on MRI scans. After a multidisciplinary reevaluation, diagnosis of PEIR was made in both cases. Both patients are followed but have not developed any disturbance related to the PEIR in the following 18 months. Conclusions: PEIR is a rare condition, probably unrecognized and the result of dysembriogenesis, which should be included in the differential diagnosis of cystic sellar lesions. Imaging features (funnel pituitary stalk and cyst in the sella) appear pathognomonic. A normal endocrine evaluation might help in the diagnosis and warrants conservative treatment.