Cause:Epidermal proliferation, though not a true neoplasia

Pathophys:Keratin layering arising in external canal or TM results in TM perforation (usually high on drum unlike OM), middle ear invasion

Sx:Conductive hearing loss; foul otorrhea several times a month; ear pain

Si:Pearl white growth seen through the drum, or, more often, within marginal perforations often in attic, posterior/superior area (pars flaccida) or filling whole canal; foul otorrhea

Progressive

Brain abscess; facial paralysis; labyrinthine fistula

Xray:CT shows erosion of adjacent bone

Rx:Surgery