[Topgraphical classification of craniopharyngioma].

Squamous cell nests of Erdheim have been observed along the lateral blood vessels to the adenohypophysis in 4 cases. Their developmental origin and topographical distribution correlate with the sites in which craniopharyngiomas are found. The theory of dysontogenic origin of cranopharyngiomas is supported by these findings. Metaplasia of cells of the adenohypophysis is not considered to be a likely cause of craniopharyngioma formation.