先天性真珠腫を合併した中耳奇形症例

抄録

A 10-year-old boy having right-ear hearing impairment since elementary school had no history of aural infection and a normal tympanic membrane. Right middle-ear anomaly was diagnosed based upon audiometric findings of 30 dB conductive hearing loss and underdevelopment of the right long incus process found in computed tomography (CT). The long process of the incus and the stapes superstructure was absent and loose fibrous change in both ossicles was found. A small ‘open’ cholesteatoma matrix occupied the area from the promontory to the lower facial canal. The lack of direct contact of the cholesteatoma matrix with ossicles and no sign of inflammation confirmed the congenital nature of this anomaly. This case points out the difficulty of diagnosing small congenital cholesteatoma despite fine CT and the need for a careful observation of the tympanic cavity during surgery.