Cholesteatoma

A cholesteatoma is a lesion of the ear, formed of a mass of stratified keratinising squamous epithelium (fig 1⇓).1 Aetiology is debated,2 but cholesteatoma probably arises from the lateral epithelium of the tympanic membrane, and then grows as a self perpetuating mass into the middle ear. This may activate local osteoclasts,3 possibly as a result of infection of dead epithelium at the centre of the lesion, with potentially serious consequences from local tissue destruction. Fig 1 Left: Cholesteatoma (red arrow) arising in the upper part (pars flaccida or "attic") of left tympanic membrane. Note erosion of surrounding bone (blue arrow). Right: Normal tympanic membrane (left ear) for comparison #### Case scenario A 24 year old man presented to his general practitioner several times over a year with an intermittently discharging left ear and associated hearing loss. Visualisation of the tympanic membrane was not possible owing to otorrhoea and oedema in the external auditory canal. He was treated for presumed otitis externa with repeated courses of topical antibiotic drops, but as improvement was only temporary he was referred to a specialist. An otolaryngologist cleared the external auditory canal of debris ("aural toilet") and discovered a cholesteatoma arising from the left tympanic membrane; this was successfully treated by surgical excision. #### How common is cholesteatoma?