Growth of cholesteatoma by implantation of epithelial tissue along the femoral bone of rats.

UNLABELLED Cholesteatoma is a well-known infection resembling a pearl. Its histological aspect is of an epidermal cyst formation characterized by epidermal-keratinized tissue in the middle ear and mastoid that can migrate and erode to adjacent structures. AIM To verify epidermal cyst (cholesteatoma) growth through implantation of auricular skin of a mouse next to its femoral bone. STUDY DESIGN Experimental. MATERIAL AND METHOD Ten healthy rats between two and five months of age and of both sexes underwent implantation of auricular skin on the femoral bone during a three-month period. Paraffin-embedded sections were obtained from the sample and stained with hematoxylin and eosin for pathology investigation. RESULTS Macroscopic view: round soft yellowish granulation tissue. Microscopic view: keratinizing stratified squamous epithelium cystic formation. The cyst presented innermost corneal layer, resulted from keratinized skin, followed by granulated and squamous layers, and outermost basal layer. CONCLUSIONS Growth of epidermal cyst (cholesteatoma) may start from a transplanted epithelial tissue next to the femoral bone of rats.