Histologic study of eustachian tube cartilage with and without congenital anomalies: a preliminary study.

We investigated histopathologically the development of the eustachian tube (ET) cartilage at a cellular level in individuals with and without congenital anomalies. Fourteen specimens were obtained from 14 individuals ranging in age from 24 weeks' gestation to 3 years who had cleft palate or trisomy 21 (Down) syndrome; the 49 specimens in the nonanomaly (control) group were from 49 individuals ranging from 26 weeks' gestation to 85 years of age. All temporal bone specimens included the ET and its accessory structures, and all were processed and stained with hematoxylin and eosin for histologic study in a routine manner. The number of cartilage cells in the midcartilaginous portion of the ET was determined by light microscopy. In all groups, cartilage cell density of the ET decreased with increasing age. However, cell density tended to be higher at all ages for individuals with cleft palate and microtia versus controls, and tended to be lower at all ages for individuals with Down syndrome.