Although cholesteatoma was first described in 1683, its etiopathogeny remains unexplained. In children, there are two forms: acquired cholesteatoma, resembling the adult form, and congenital cholesteatoma. The acquired form has become less frequent in recent years, thanks to progress in the treatment of childhood otitic pathology. Diagnosis of congenital cholesteatoma, on the contrary, is increasing, due to improvements in information to health care professionals and in diagnostic tools. Clinical and histological evidence points to greater aggressiveness in childhood forms, although this difference cannot, at present, be precisely explained. Diagnosis is clinical, but CT and MR imaging is indispensable for preoperative assessment and postoperative follow-up. New delayed gadolinium-enhanced T1-weighted and diffusion-weighted MRI sequences have recently been developed and provide more precise radiological diagnosis. Treatment is surgical; alternatives, notably by laser, have proved unsuccessful. Complications concern involvement of neighbouring structures, and are mainly infectious; some can be life-threatening, and should be systematically screened.