Unicystic Ameloblastomatoid Cystic Craniopharyngioma: Pathological Discussion and Clinical Significance of Cyst Formation in Adamantinomatous Craniopharyngioma.

An 8-year-old boy presented complaining principally of headache and vomiting. A single large cystic lesion extending from the suprasellar region to the ventral brainstem was identified, and total extirpation was performed via a right orbitozygomatic, transtemporal transchoroidal fissure approach. The cyst contents resembled motor oil, and no strong adhesions were identified between the tumor and the surrounding tissue except at the site of origin of the tumor, allowing easy dissection. The tumor originated at the junction of the adenohypophysis and the pituitary stalk. Although the histopathological diagnosis was adamantinomatous craniopharyngioma, the cyst walls comprising the majority of the tumor were not thin, fragile tissues formed by squamous metaplasia, but were thick and robust, bearing a close resemblance to unicystic ameloblastoma mixed with solid tissue. The existence of this type of cyst wall represents corroborating evidence that craniopharyngiomas are derived from the oral primordium. The existence of such tumors that can be totally extirpated in a single procedure while preserving hypothalamo-pituitary function may be taken as a warning not to rush at random to perform treatments that might encourage recurrence or regrowth by carrying out cyst fenestration and drug injection with the addition of stereotactic radiotherapy.