Scanning and transmission electron microscopy of the rugose portion of the human endolymphatic sac--a preliminary report.

The rugose portion of two human endolymphatic sacs--one from a Meniere's disease patient, the other from a patient who underwent removal of an eighth nerve tumor and had no other evidence of inner ear disease--has been examined by scanning and transmission electron microscopy. The only morphological finding that distinguished the normal from the Meniere's disease specimen was more folds in the epithelium of the normal sac. Two types of cells have been distinguished in the two sacs through both scanning and transmission electron microscopy: cuboidal-to-columnar cells with a convex luminal surface and microvilli, and squamous cells with a flat luminal surface and microvilli. Qualitative differentiation of the two specimens according to frequency of cellular type or difference in cellular or microvillar morphology was not possible. Observations of this study on the epithelial morphology of the rugose portion did not correspond with descriptions of the epithelial morphology in animals. It is, therefore, tentatively concluded that the morphology of the rugose portion of the human endolymphatic sac is different from that of animals. This study suggests that scanning electron microscopy can be used to determine the number and location of cell types and/or the quantity of microvilli in the rugose portion of the endolymphatic sac. Comparison of measurements of normal endolymphatic sacs and those from Meniere's disease patients may demonstrate significant differences.