An unusual congenital middle ear ossicular anomaly.

Unilateral congenital absence of the stapes suprastructure occurred in association with displaced attachment of the stapedial tendon on an abbreviated incudal lenticular process. The stapes footplate was intact and mobile, and the middle ear was otherwise normal. This is interpreted to be a developmental aberration involving partial absence of a second branchial arch derivative. The preoperative history of no trauma or surgery and the audiologic analysis correlated with the occurrence of this anomaly. This appears to be the first reported case of this unusual congenital anomaly. In addition, it adds a unique item to the differential diagnosis of the pathologic features implicated in an ear with a conductive deficit, intact stapedius reflex, and tympanogram consistent with ossicular discontinuity.