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

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.