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Immunohistochemical investigations on external auditory canal cholesteatomas
Melanie Adamczyk1, Holger Sudhoff, Klaus Jahnke
1Department of Otorhinolaryngology, University of Essen, Essen, Germany. melanie.adamczyk@uni-essen.de
Objective:
The aim of the study was to analyze the biological behavior of external auditory canal cholesteatoma (EACC). The expression and distribution of relevant markers such as transforming growth factor-alpha (TGF-alpha), epidermal growth factor-receptor (EGFR), and the proliferation marker MIB 1 were studied in comparison with normal auditory meatal skin.
Background:
EACC are uncommon and knowledge concerning etiology and pathogenesis is limited. Whether this is a unique entity remains controversially discussed.
Materials And Methods:
Immunohistochemical methods were used to study the expression and distribution TGF-alpha, EGFR, and the proliferation marker MIB 1 on 15 tissues samples. Only the spontaneous form of EACC was included in this study.
Results:
Positive immunoreactivity for the proliferation marker MIB 1 could be demonstrated in keratinocytes in the basal and suprabasal layers of the epithelium. The number of MIB 1-positive proliferating cells in cholesteatoma was significantly higher than in normal external auditory skin. Cholesteatoma epithelium also showed an enhanced expression of TGF-alpha and EGFR. Inflammatory infiltrate was observed in the perimatrix to various degrees.
Conclusion:
These results suggest that similar to the middle ear cholesteatoma, a chronic inflammatory process underlies the EACC, and the inflammatory stimuli may alter keratinocyte proliferation.