Figure 1: (A) Incus: Normal bone tissue histomorphology and regular ossicle architecture are present. Arrows: features of fibrous connective tissue on the surface. (B) An incus, showed evident features of fibrous connective tissue on the surface and inflammation (arrows). (C) Malleus head: On the surface, residual disease with squamous epithelium was observed. Inflammatory cells infiltration was present in the perimatrix. Arrows: keratinizing squamous epithelium in residual cholesteatoma; all remnant disease are superficial. (D) Malleus head: Squamous epithelia Pan-CK expression was normally seen in the whole layers of squamous epithelia. Arrows: epithelial tissue in residual cholesteatoma. (L.M., Stage I Ematoxilin-Eosin stain Original magnification 20x; L.M., Stage III Immunoistochemistry, IHC, staining to evaluate Pan-CK expression Original magnification 20x).