Temporal bone histopathology: Superior semicircular canal dehiscence

OBJECTIVES

To present a histopathological case of a 91-year-old woman who was diagnosed with superior semicircular canal dehiscence postmortem.

METHODS

The patient was a registered donor with the National Temporal Bone Donor Program at the NIDCD National Temporal Bone, Hearing and Balance Pathology Resource Registry. Computed tomography imaging was performed on each temporal bone. The temporal bones were decalcified with ethylenediaminetetracetate and embedded in celloidin, and tissue sections were stained with hematoxylin and eosin. Horizontal sections were taken through the left temporal bone, and vertical sections were taken through the right temporal bone.

RESULTS

Histopathological sections taken through the right temporal bone demonstrated no bone between the membranous wall of the superior semicircular canal and the middle fossa dura. There was no histopathological evidence of superior semicircular canal dehiscence in the left temporal bone; however, a small dehiscence would not be identified on horizontal sections. Microcavitations were observed in the common crus of the left temporal bone.

CONCLUSION

This reports describes the case of a woman who was diagnosed with superior semicircular canal dehiscence postmortem. The presence of microcavitations in the temporal bone is consistent with osteoclastic activity, which may play a role in the development of superior canal dehiscence.

Otopathology in Angiosarcoma of the Temporal Bone

OBJECTIVES/HYPOTHESIS

Investigate the otopathology of angiosarcoma of the temporal bone, which has not been previously described in the literature.

STUDY DESIGN

Postmortem evaluation and literature review.

METHODS

Postmortem histological evaluation of the temporal bones and review of the literature for the treatment and prognosis of this rare disease were performed.

RESULTS

A 50-year-old male with right chronic otitis media presented with progressive hearing loss, disequilibrium, otalgia, and acute facial paresis. Biopsy of the external auditory canal was unrevealing, but specimens from a canal wall down tympanomastoidectomy later showed high-grade angiosarcoma. Magnetic resonance imaging demonstrated an unresectable middle ear and mastoid mass extending superiorly into the temporal lobe. The patient received induction chemotherapy followed by proton beam radiation therapy and concurrent paclitaxel and bevacizumab. His course was complicated by a cerebrospinal fluid leak and cauda equina syndrome from leptomeningeal sarcomatosis. The patient died after developing meningitis and a temporal lobe abscess. Postmortem otopathology revealed persistent angiosarcoma in the internal auditory canal, although none was found in the middle ear or mastoid. There was inflammatory infiltrate throughout the mastoid, with direct extension of neutrophils and bacteria into the cochlea and through the tegmen into the middle cranial fossa.

CONCLUSIONS

Angiosarcoma of the temporal bone can arise in the setting of chronic otitis media. In this case, postmortem temporal bone sections demonstrated viable cancer despite chemoradiation. Inflammatory infiltrates crossing from the middle ear/mastoid into the labyrinth and central nervous system illustrate pathways for the development of otogenic meningitis.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:737-742, 2019.

Auditory analysis of xeroderma pigmentosum 1971-2012: hearing function, sun sensitivity and DNA repair predict neurological degeneration

To assess the role of DNA repair in maintenance of hearing function and neurological integrity, we examined hearing status, neurological function, DNA repair complementation group and history of acute burning on minimal sun exposure in all patients with xeroderma pigmentosum, who had at least one complete audiogram, examined at the National Institutes of Health from 1971 to 2012. Seventy-nine patients, aged 1-61 years, were diagnosed with xeroderma pigmentosum (n = 77) or xeroderma pigmentosum/Cockayne syndrome (n = 2). A total of 178 audiograms were included. Clinically significant hearing loss (>20 dB) was present in 23 (29%) of 79 patients. Of the 17 patients with xeroderma pigmentosum-type neurological degeneration, 13 (76%) developed hearing loss, and all 17 were in complementation groups xeroderma pigmentosum type A or type D and reported acute burning on minimal sun exposure. Acute burning on minimal sun exposure without xeroderma pigmentosum-type neurological degeneration was present in 18% of the patients (10/55). Temporal bone histology in a patient with severe xeroderma pigmentosum-type neurological degeneration revealed marked atrophy of the cochlear sensory epithelium and neurons. The 19-year mean age of detection of clinically significant hearing loss in the patients with xeroderma pigmentosum with xeroderma pigmentosum-type neurological degeneration was 54 years younger than that predicted by international norms. The four frequency (0.5/1/2/4 kHz) pure-tone average correlated with degree of neurodegeneration (P < 0.001). In patients with xeroderma pigmentosum, aged 4-30 years, a four-frequency pure-tone average ≥10 dB hearing loss was associated with a 39-fold increased risk (P = 0.002) of having xeroderma pigmentosum-type neurological degeneration. Severity of hearing loss parallels neurological decline in patients with xeroderma pigmentosum-type neurological degeneration. Audiometric findings, complementation group, acute burning on minimal sun exposure and age were important predictors of xeroderma pigmentosum-type neurological degeneration. These results provide evidence that DNA repair is critical in maintaining neurological integrity of the auditory system.

Histopathologic features of the temporal bone in usher syndrome type I

Temporal bones of 2 patients with Usher syndrome type I were examined using light microscopy. In both patients, findings from histopathologic examination of the cochlea were characterized by degeneration of the organ of Corti, which was most marked in the basal turn, atrophy of the stria vascularis, and a decrease in the number of spiral ganglion cells. The cochlear nerve appeared to be diminished. The sensory epithelium of the saccular and utricular maculae of patient 1 was normal for age. The left temporal bone of patient 2, classified as Usher syndrome genetic subtype USH1D or USH1F, demonstrated the typical signs of severe cochleosaccular degeneration. Present cases and cases from the literature were reviewed in search of an explanation for the above-described differences in histologic findings.

Correlation between antibodies to type II collagen and treatment outcome in bilateral progressive sensorineural hearing loss

Our aim was to assess whether "idiopathic" bilateral progressive sensorineural hearing loss (BPSHL) has an immunological cause in some patients; antibodies to native type II collagen were sought by an ELISA in eighteen patients with BPSHL, before and after corticosteroid treatment, and in twelve patients with Menière's disease, fifteen with otosclerosis, eighteen with rheumatoid arthritis, nine with fibrositis, and nine healthy controls. A positive result was defined as a mean dilution titre of 2 or more. Eight of eighteen BPSHL patients had positive titres--significantly (p less than 0.005) more than in any other group (one Menière's disease, two otosclerosis, and no others). The mean antibody titre was higher in the BPSHL group than in any other group (2.02 [SEM 0.62] vs 0.17 [0.17]) Menière's disease, 0.44 [0.32] otosclerosis, 0 all others; p less than 0.005). The nine BPSHL patients who showed a clinical response to corticosteroids (improvement in at least one tone by audiogram or 25 db in speech discrimination score) had the highest mean antibody titre (3.46 [0.88] vs 0.59 [0.59] for the nine non-responsive patients; p less than 0.04). We suggest that in some patients with BPSHL, immunity to type II collagen, a major constituent of the inner ear, may be important in the pathogenesis of the disorder.