Craniopharyngioma causes
Craniopharyngioma causes
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Marjan Khan M.B.B.S.[2]
Overview
There are two histological phenotypes seen in craniopharyngioma; the adamantinomatous tumours, seen in children, that resemble enamel forming neoplasm's in the oropharynx and the squamous papillary form, predominantly seen in adults. The characteristic location of these tumours in the sellar and para-sellar region, together with the different histological subtypes, allows for two theories that may explain the origin of these tumours.
Causes
- Craniopharyngioma is a nonglial intracranial tumor derived from a malformation of embryonic tissue.
- There are differing hypotheses on its embryonic origin.
- The caause of craniopharygioma is although not completely understood.
- Some authorities advocate that it originates from ectodermal remnants of Rathke's pouch.
- Few pathologists believe that it originates from residual embryonal epithelium of the anterior pituitary gland and of the anterior infundibulum.
Embryonic theory
- According to this theory Craniopharyniomas arise from neoplastic transformation of embryonic squamous cell nests of Rathke's pouch with the stomodeum.
- During the process of proliferation and rotation of the cells of Rathke's pouch leading to the formation of the adenohypophysis, cell remnants of the craniopharyngeal *duct are spread through the intrasellar and suprasellar region.
- The rotation of the adenohypophysis is caused by different rates of cellular multiplication, resulting in a spread of cells of the craniopharyngeal duct to the suprasellar region.
- The rare location at the cerebellopontine angle could fit with this hypothesis.
Metaplastic theory
- Papillary craniopharyngiomas are the result of metaplasia of the adenohypophyseal cells in the anterior pituitary, resulting in the formation of squamous cell nests.
- This theory is supported by the presence of metaplastic nests in the gland
Genetics
- Multiple chromosomal abnormalities have been reported by classic cytogenetic analysis.
- Most tumors had abnormalities involving chromosomes 2 and 12.
- More than 70% of adamantinomatous craniopharyngiomas harbor a mutation of the β-catenin gene.
- Most of the mutations affect exon 3, which encodes the degradation targeting box of β-catenin compatible with an accumulation of nuclear β-catenin protein.
- In a few cases of adamantinomatous craniopharyngioma, the same β-catenin mutations occurring in the epithelial cells have been identified in mesenchymal cells.
- No mutations have been demonstrated in papillary craniopharyngioma.