Persisting embryonal infundibular recess (PEIR) and transsphenoidal-transsellar encephaloceles: distinct entities or constituents of one continuum?

Abstract

Persisting embryonal infundibular recess (PEIR) is a very rare anomaly of the floor of the third ventricle in which the embryonic morphology of the infundibular recess (IR) persists. The exact underlying mechanism of development of PEIR is unknown, and the anomaly has been reported as an isolated finding or in association with other conditions. On the other hand, trans-sphenoidal encephaloceles are the rarest form of basal encephaloceles. The trans-sphenoidal trans-sellar encephalocele (TSE) is the least common variant in which the pituitary gland, pituitary stalk, optic pathways, parts of the third ventricle and IR may be present within the encephalocele. We recently treated one patient with TSE. Based on the observed morphological similarity of the IR in our patient and in the published cases of PEIR, we reviewed the literature in order to validate the hypothesis that PEIR and TSE may possibly belong to one spectrum of malformations. Across the published reports, the morphology of the IR in TSE is very closely similar to PEIR. Moreover, radiological, patho-anatomical, and embryological evidence is in support to our hypothesis that PEIR and TSE are most likely the two extremes of the same continuum of malformations.

Keywords: Endoscopic; Persisting embryonal infundibular recess (PEIR); Transsphenoidal transsellar encephalocele.