Learning Objectives:

Being a potential life-threatening middle ear disease, cholesteatoma is an abnormal expanding cystic lesion leading to extensive tissue destruction in the temporal bone followed by conductive and sensorineural hearing loss and facial nerve palsy. Facilitating further infections beyond those of the middle ear, cholesteatoma may also result in meningitis or intracranial infections. Since surgical removal of cholesteatoma remains as the only therapeutical option, lack of non-advanced medical care results in increased pediatric morbidity, emphasizing the need of developing new treatment strategies.

Here we show for the first time the presence of a novel stem cell-like cell population in cholesteatoma tisse and auditory canal skin. Immunohistochemical analysis of cholesteatoma tissue revealed the presence of Nestin-expressing cells localized subepithelially within the matrix and perimatrix. Nestin-positive cholesteatoma-derived stem-like cells (CSCs) were successfully isolated and cultivated in vitro and showed the capability of neurosphere formation and clonal growth. CSCs were further successfully expanded within a human blood-plasma derived three-dimensional matrix. In accordance to the classification of cholesteatoma, proliferative Ki67-positive CSCs also showed a normal euploid DNA content and karyotype. We further observed no changes in proliferative capability and expression profile between CSCs and Nestin-expressing cells isolated from auditory canal skin (auditory skin derived cells, ASCs). In particular, cultivated CSCs and ACCs expressed epithelial and neural crest-specific stemness markers.

Our findings gain new insights in the complex biology of cholesteatoma and may thus broaden the range of treatment strategies for this severe lesion within the middle ear.