A persistent craniopharyngeal canal harboring adenohypophyseal lineages associated with Rathke's cleft cyst: illustrative case.

backgroundThe craniopharyngeal canal (CPC) is a rare developmental remnant of Rathke's pouch and is occasionally associated with Rathke's cleft cysts (RCCs) and ectopic pituitary tissue. Although embryological and radiological studies have proposed a developmental continuum among these entities, pathological characterization of residual pituitary tissue within CPC remnants in adult patients remains limited. OBSERVATIONS: A 40-year-old woman presented with visual field impairment secondary to suprasellar RCC. Endoscopic endonasal surgery revealed a bony canal extending through the sphenoid sinus from the sellar floor to the posterior pharyngeal wall, consistent with a persistent CPC. Histologically, the canal tissue contained nests of adenohypophyseal cells within a fibromuscular stroma. Immunohistochemical analysis expressed pituitary lineage-specific transcription factors, including PIT-1, with focal SF-1 and T-Pit positivity, which indicate multiple adenohypophyseal lineages. Intraoperative observations of the cystic cavity revealed a dimple-like structure at the corresponding anatomical site. LESSONS: This case demonstrates that pituitary tissue may persist within a type 1 CPC on imaging. Moreover, residual adenohypophyseal cells within the canal can exhibit multiple lineage-specific transcription factor profiles, supporting a spectrum of developmental arrest in Rathke's pouch remnants. https://thejns.org/doi/10.3171/CASE25671.