Mucosa-associated lymphoid tissue in middle ear and Eustachian tube in children.

The presence of mucosal lymphoid follicles with germinal centers, so called mucosa-associated lymphoid tissue (MALT), in the Eustachian tube (ET) and middle ear (ME) was investigated in 23 human temporal bones containing the entire ET obtained from 23 children, 3 months to 10 years old at death. Greater numbers of MALTs were found in specimens from children with otitis media (OM) than from those without OM. MALT showed a wedge-shaped distribution through the ME and ET: in all 3 specimens that had MALTs in the ME, these tissues were seen throughout the ET; in all 4 specimens with MALTs in the bony portion of the ET, these tissues were present both in the tympanic and pharyngeal portions of the cartilagines ET; all 7 specimens that had MALTs in the tympanic half of the cartilagines ET had MALTs in the pharyngeal portion of the cartilagines ET as well. Furthermore, MALTs were noted in the pharyngeal portion of the ET in more than half of the specimens without OM but in none of the MEs of specimens without OM. These results support the hypothesis that persistent and recurrent inflammation in the nasopharynx spreads through the ET to play a role in the pathogenesis of chronic OM in children.