Histopathological study on temporal bone and eustachian tube in trisomy 22

Two temporal bone-eustachian tube (ET) specimens, one from a 34-gestational week-old male newborn and the other from a 3-month-old female infant, both with trisomy 22, were studied histopathologically. Both cases demonstrated severe inner-ear anomalies including hypoplastic cochlea, atrophy of the saccular macula, and dislocated endolymphatic sac and vestibular aqueduct. In addition, they had several anomalies in the ET including widely developed medial lamina of the ET cartilage, undeveloped lateral lamina of the ET cartilage, and absence of attachment of the tensor veli palatini muscle to the ET cartilage. We discuss the implications of the observed anomalies with regard to developmental and clinical issues.