OTOCEPHALUS - HISTOPATHOLOGY AND 3-DIMENSIONAL RECONSTRUCTION

Otocephaly is a lethal malformation of the first and second branchial arches, which consists of ventromedial displacement of the external ea r structures (synotia), mandibular aplasia (agnathia), absence of the tongue (aglossia), and microstomia. We present the first complete desc ription of the temporal bone findings in a case of otocephalus. A thre e-dimensional computer-assisted reconstruction of the right temporal b one was performed, allowing a unique graphic analysis, An extremely lo w-lying middle fossa tegmen was noted with malrotation of the middle e ar structures, Severe ossicular malformations were also found, An anom alous course of the internal carotid artery was noted with indentation of the basal turn of the cochlea, All three layers of the otic capsul e were incompletely developed, Cochlear bony dehiscences were noted. T hese findings are consistent with early arrest of fetal development an d malrotation caused by lack of growth pressure from the mandibular ar ch, Implications of these findings in the embryologic development of t he ear are discussed.