Cholesteatoma is a proliferative disease of the middle ear with bone resorption activity. Its pathogenesis remains controversial and has yet to be clarified. Cytokeratins represent a well-known epithelial proliferative and differentiation markers. In the current study, we investigated expression of a large set of cytokeratins in cholesteatoma matrix versus deep meatal skin tissues from the same patients.
An immunohistochemical study was carried out using acquired cholesteatoma (n = 15) and deep meatal skin tissues (n = 6). Mouse monoclonal antibodies were used against cytokeratin 5/6 (CK5/6), cytokeratin HMW (CKHMW), Cytokeratin 10 (CK10), Cytokeratin 14 (CK14) and Cytokeratin19 (CK19). The indirect immunoperoxidase method for immunostaining was employed. Both pattern and intensity of expression of those cytokeratins were evaluated and compared in cholesteatoma and skin tissues.
With the exception of CK19, all studied cytokeratins were expressed in cholesteatoma matrix and epidermis of meatal skin. In addition, a typical pattern of expression was observed between both tissues. No significant difference in the intensity of expression was found (p > 0.05). CK HMW and CK5/6 were expressed in all layers of cholesteatoma epithelium and meatal skin. CK10 was expressed in suprabasal keratinocytes whereas CK14 was expressed in basal, parabasal and to lesser extent in suprabasal cholesteatoma and skin layers.
Cytokeratins are similar in their distribution in both skin and cholesteatoma tissues. These findings support the immigration theory and confirm the proliferative nature of cholesteatoma. However, more research is needed to clarify how this knowledge can affect the future management of acquired cholesteatoma.