A giant mastoid cholesteatoma with posterior cranial extension causing mass effect and obstructive hydrocephalus

摘要

Cholesteatoma is a benign, keratinizing lesion with proliferation of epithelial cells in the middle ear. Cholesteatomas are divided into acquired and congenital (primary) subtypes.'Acquired cholesteatomas usually occur in the middle ear with rare extension to the petroux apex unlike congenital cholesteatomas. These lesions are postulated to be ectopic rests of embryologic epithelial tissue in the petrous apex, which failed to undergo involution. As internal desquamation occurs from the stratified squamous epithelium, keratinized debris accumulates centrally and forms a highly organized structure. The advancing epithelium combined with host inflammatory response results in surrounding bone resorption [1 ]. The chronicity of this benign process may cause adjacent bone remodeling and mass effect without early clinical signs.