AIM: A comparative analysis between the histological and the immuno histochemical (Ki-67 and CK-16) characteristics of spontaneous cholesteatomas of the external ear canal and acquired cholesteatomas of the middle ear was carried out. STUDY DESIGN: Case-control. MATERIAL AND METHOD: Fragments of external ear canal cholesteatomas were submitted to histological and immunohistochemical studies to evaluate the expression of CK-16 and of the nuclear antigen Ki-67 in the matrix cells. Results were compared to the same studies in acquired cholesteatomas of the middle ear. RESULTS: Histological and immunohistochemical aspects studied were identical in both types of cholesteatomas studied. DISCUSSION: This study suggests that cholesteatomas of the external ear canal are caused by na abnormal behavior of the cells of the epithelium of the external canal with hyperproliferative properties. This potential could be explained by the presence of CK-16 at a location where these markers are not usually found. The hyperproliferative characteristic of the external ear canal cholesteatoma is possible due to the presence of the K-67 nuclear antigen in the epidermal suprabasal cells. It is possible that the disease is caused by an interaction between CK-16 and the cytocines (TGF-alpha),which are present in the subepithelial connective tissue undergoing na inflammatory process. CONCLUSIONS: The histological (presence of epithelial cones) and immunohistochemical (expression of CK 16 and the nuclear antigen KI-67) characteristics of both the external ear canal and the acquired middle ear cholesteatomas are identical.
cholesteatoma; external ear canal; middle ear; CK16; KI-67
