Both temporal bones were nearly identical (except as noted) and are described together. The external auditory canal, tympanic membrane, ossicles, middle ear and mastoid air spaces, and the otic capsule appeared normal. Peritubal air cells were present, while the petrous apices were not pneumatized. Preservation of cytologic elements within the inner ear was excellent.
The apical halves of both cochleae (16–32 mm regions, i.e., the upper basal, middle and apical turns) showed severe atrophy and degeneration of inner and outer hair cells, tectorial membranes and the striae vasculares, as shown in cytocohleograms in and photomicrographs in . The organs of Corti were completely missing or represented by a mound of supporting cells with missing hair cells. The tectorial membranes showed marked pathologic change, characterized by cellular encapsulation and detachment from the spiral limbus. Tectorial membrane pathology was more extensive in the left ear, extending further towards the base than in the right ear. The lateral cochlear walls showed near-total atrophy of the striae vasculares and severe degeneration of fibrocytes of the spiral ligament. The fibrocytes of the spiral ligament appeared to have been replaced by connective tissue cells. The spiral limbi showed patchy atrophy.
Otopathologic findings in the right ear
Within the basal halves of both cochleae (0–16 mm regions, i.e., the lower basal turn), the hair cells, supporting cells, tectorial membranes, spiral limbi, and spiral ligaments were generally present and appeared normal for age. The striae vasculares were generally intact except for patchy atrophy in the 3–7 mm region on the right and 0–3 mm region on the left.
Cochlear neurons were present in numbers that were normal-for-age (total count, 23,796 on right, 24,255 on left). The central axons of the spiral ganglion cells were also present. Whereas dendrites leading up to the organ of Corti were well preserved in the distal part of the osseous spiral lamina of the basal turn, they were atrophied in the middle and apical turns.
Reissner’s membrane was in normal position in both cochleae except for apical (non-pathologic) hydrops. The scalae media of the middle and apical turns showed scattered cellular debris which appeared to be the result of sloughing of cells that were degenerating from within the striae and organs of Corti. The fluid spaces did not show any hemorrhage, or deposition of fibrous tissue or new bone.
The vasculature of the cochleae was examined. Branches of the main cochlear artery within the modiolus were patent. Similarly, the external and internal radiating arterioles were also patent. However, some capillaries of the stria vascularis showed apparent occlusion of the lumen by an acellular substance or by thickening of the vessel wall. The number of capillaries appeared to be less than normal in the lateral cochlear wall of the middle and apical turns (in areas corresponding to the severe atrophic changes). The collecting venules and the posterior spiral vein appeared unremarkable.
The vestibular sense organs, including the saccules, utricles and all three semicircular canal cristae showed good populations of hair cells, supporting cells, and innervating dendrites (probably normal for age) in both ears, except for the saccular macula in the left ear which showed a diminution of type I hair cells. The membranous vestibular labyrinths were normal, without collapse or hydrops. The lumen of the saccule in both ears contained free-floating cells arranged in strands and folded strips. The origin of these cells was obscure; they could possibly be cells that line the saccular duct and which became detached. Blood vessels supplying the vestibular labyrinths appeared normal. There was a good population of cells within Scarpa’s ganglion in both ears, probably normal for age. The facial nerves and canals were normal.
The leptomeninges within both internal auditory canals showed a large number of psammoma bodies, more than what is seen on average in a normal ear. In addition, many small arterioles within the leptomeninges showed a peculiar thickening of the vessel wall to the point of occlusion. In some instances, it appeared that there was proliferation of cells within or around the wall causing the occlusion, while in other instances there was a dense basophilic material occluding the vessel lumen. There was a general absence of inflammatory cells within the vessel walls.