The ultrastructure of the endolymphatic sac in man.

The present investigation describes the ultrastructure of the human endolymphatic sac in surgical biopsy specimens from 14 patients with acoustic neuroma and Ménière's disease. The intent of the study is to illustrate the normal appearing human endolymphatic sac by transmission electronmicroscopy (TEM) and to detail histopathologic alterations which occur in patients with acoustic neuroma and Ménière's disease. Normal endolymphatic sac histology is elucidated and provides a basis for discussing pathologic changes seen in disease states. The endolymphatic sac undergoes similar histopathologic changes in patients with acoustic neuroma and Ménière's disease. Epithelial degeneration, thickening of the basilar lamina and perisaccular fibrosis appear in both disease processes. The presence of similar pathologic changes in the endolymphatic sac patients with acoustic neuroma and Ménière's disease suggests that the sac degeneration is the result of the disease process and not necessarily its cause.