Lymphoma invading the anterior eustachian tube. Temporal bone histopathology of functional tubal obstruction.

The temporal bones of a man with poorly differentiated lymphocytic lymphoma, who had had a bilateral conductive hearing loss and incomplete left-sided facial palsy, were obtained. Sections were prepared for histologic study by staining with hematoxylin and eosin and were examined under the light microscope. The left temporal bone showed marked tumor cell involvement, not only of the lateral part of the cartilaginous portion of the eustachian tube (ET) where the tensor veli palatini muscle had been partially destroyed, but also in the anterior part of the temporal bone. A serous middle ear effusion was present, but the lumen of the ET was unaffected by tumor or inflammation. The pathological findings in the right temporal bone were similar to those in the left, although the cartilaginous part of the ET and its surrounding structures were not available for study. The pathogenesis of otitis media with effusion appeared to be secondary to functional ET obstruction, due to the dysfunction of the tensor veli palatini muscle as a result of the tumor destruction. This case is the first to be reported in which functional ET obstruction, secondary to tumor invasion of the active muscle dilator of the ET, has been histologically confirmed.