Background: Ectopic craniopharyngioma is an uncommon entity. We report the first case of ectopic craniopharyngioma confined purely within the fourth ventricle, exophytic from pons.

Methods: A 12-year-old girl presented with 2 months history of headache and recent evidence of raised intracranial pressure and left abducent palsy. Magnetic resonance imaging suggested intra-fourth ventricular mass with hydrocephalus. The patient underwent midline posterior fossa craniotomy and tumor excision, with prompt relief of gaze palsy. Histologic examination proved the lesion to be craniopharyngioma. We found no evidence to correlate this tumor to the suprasellar region.

Conclusions: Craniopharyngioma may not always be in primary communication with suprasellar tumor.