Temporal bone histopathological features of a worker who received high doses of radiation in a criticality accident: a case report.

In 1999, three workers received high doses of radiation in a small Japanese plant while they were preparing fuel for an experimental reactor. This criticality accident at melting point was caused by the addition of too much uranium enriched to a relatively high level, causing a 'criticality' (a limited uncontrolled nuclear chain reaction), which continued intermittently for 20 h. The three workers concerned were hospitalized, two in a critical condition. The first worker died 12 weeks later, and the second worker 7 months later. The third worker is in a healthy condition. We report on the temporal bone histopathological features of the second worker. Our temporal bone study revealed: 1) the large loss of bone marrow tissue with a small number of myelocytes remaining in the mastoid bone and the abundance of fatty tissue in the mastoid bone, 2) inflammation of the mucosal layer of the middle ear and the mastoid air cells, 3) mild degeneration of the spiral ganglions and the sensory hair cells of the cochlea, 4) mild degenerative changes of sensory hair cells of the semicircular canals and otolith organs, and 5) vestibular ganglions and geniculate ganglions were well preserved.

Temporal bone pathological study on maxillary sinus carcinoma with bilateral temporal bone metastasis.

We report a case in which metastasis occurred from a left-side maxillary carcinoma to bilateral temporal bones through different routes, manifested by rapidly progressing left-side mixed hearing loss, left-side vestibular dysfunction, and serous otitis media. Later the left-side hearing threshold became severely elevated, suggesting profound sensory hearing loss. Histopathology of the temporal bones revealed that the side with the lesion was severely damaged by tumor through direct and hematogenous metastasis. On the contralateral side, it showed four findings: (i) sparse and separate tumor invasion of the petrous bone, the mastoid cavity, and the facial canal (hematogenous spread); (ii) tumor involvement in the lower part of the cochlear aqueduct without invasion of the internal acoustic canal or cochlea, implying early meningeal carcinomatosis; (iii) vascular stria atrophy, spiral ganglion diminution, and well preserved hair cells; and (iv) diffuse effusion in the middle ear and mastoid cavity. Our observations revealed that tumor cells dispersed to the same side through different routes, whereas early metastasis to the contralateral side was mainly through hematogenous and subarachnoid spread.

Changes in the audiograms of a nasopharyngeal cancer patient during the course of treatment: a temporal bone histopathological study.

This report shows the changes that occurred in consecutive audiograms of a patient who underwent chemotherapy and radiotherapy for nasopharyngeal cancer and the histopathological examination of the temporal bones. Both conductive and sensorineural hearing loss developed, but followed different modes of progression. In the left ear, an air-bone gap appeared and deepened, while in the right ear, severe conductive hearing loss was present upon admission and improved after treatment. Sensorineural hearing loss was worse in the right ear, but deteriorated gradually in both ears. Histology revealed tumor invasion in the right temporal bone. Both middle ears showed effusion, but no radiation-induced changes that may be responsible for the conductive loss. The main changes in the cochlea were vascular stria degeneration, spiral ligament atrophy, and spiral ganglion cell depletion, while the hair cells were only occasionally missing. Apart from confirming what has been established previously by other authors, some interesting findings were observed: (1) in addition to the high frequency hearing loss typically caused by cis-platinum and by radiation, there was also low frequency hearing loss, and (2) the cochlear damage was most severe in the vascular stria and spiral ganglions, sparing the hair cells.

Tuberculous meningitis-induced unilateral sensorineural hearing loss: a temporal bone study.

The relationship between meningitis and sensorineural hearing loss (SNHL) has long been studied. Many histopathological studies of animal models and human temporal bones with respect to bacterial meningitis have been carried out. However, the relationship between SNHL and tuberculous meningitis was seldom addressed and the pathophysiology remains unclear. We carried out temporal bone studies on material from a 22-year-old patient who developed a right unilateral SNHL before dying from tuberculous meningitis. The histopathological findings for the right temporal bone were as follows: (1) inflammation mainly appeared in the internal auditory canal, modiolus and Rosenthal's canal and extended to the osseous spiral ligament, whereas the perilymphatic spaces were less involved; (2) the organ of Corti, cochlear nerve fibres and spiral ganglion cells were severely degenerated, particularly in the basal and middle turns; (3) the contralateral side (for which the patient had no complaints) showed an inner space free from inflammation, but some granulomatous formations were observed in the middle ear cavity. We conclude that the modiolus and cochlear aqueduct are the main routes for the spread of infection from the meninges to the inner ear. The progression of hearing loss resembles that of bacterial meningitis and shares attributes of retrocochlear SNHL.

Are vestibular sensory cells preserved after destruction of Scarpa's ganglion? A study based on metastatic tumors of temporal bone.

OBJECTIVE: The contribution of nerve fibers to the maintenance of vestibular sensory cells is a controversial issue in previous studies using animals and has not yet been studied in humans. The authors investigated this issue by observing vestibular end organs in the temporal bone of three patients in whom the internal auditory canal was infiltrated with tumor cells, and Scarpa's ganglion cells showed complete degeneration. STUDY DESIGN: Retrospective case review. SETTING: University Hospital, Department of Otolaryngology. PATIENTS: Three patients with malignant metastatic temporal bone tumors. INTERVENTION: We investigated the preservative state of vestibular sensory hair cells with the Scalpa's ganglion was destructed. MAIN OUTCOME MEASURES: Maintenances of vestibular sensory hair cells. RESULTS: We found that sensory cells were intact despite the severe destruction of Scarpa's ganglion cells in two of the patients. CONCLUSION: The findings suggest that human vestibular sensory cells can be maintained for an indefinite period after denervation.

Temporal bone pathology in hydrocephalus: changes in the inner ear due to increased intracranial pressure.

Changes in the inner ear due to increased intracranial pressure have not yet been clearly defined. We present a postmortem temporal bone study of child with hydrocephalus. The temporal bone was from a 2-year-old female with IVth ventricle ependymoblastoma. In the basal turn of the cochlea, degeneration of the organ of Corti and the nerve ganglion was observed. In the top and middle turn, structures were intact. The utricle and saccule were well preserved. We propose that changes in the inner ear due to increased intracranial pressure begin in the base of the cochlea, and extend to the apex in decreasing degree.

Audiovestibular findings in patients with mitochondrial A1555G mutation.

OBJECTIVE: The aims of this study were to explore the prevalence of the A1555G mutation among a group of Japanese patients and to assess the pathophysiology of the hearing impairment associated with the mutation. STUDY DESIGN: Genetic study and retrospective chart review. METHODS: We screened for the mitochondrial DNA A1555G mutation in 138 unrelated Japanese deaf patients, including 63 sporadic cases and 75 familial cases with different patterns of inheritance. When available, patients carrying the mutation received audiovestibular examinations, including speech audiometry, distortion-product otoacoustic emission (DPOAE) testing, electrocochleography (ECochG), and electronystagmography. RESULTS: One of 63 sporadic cases (1.6%) and 6 of 75 familial cases (8.0%) carried the A1555G mutation. Patients with the mutation and a familial history included two with autosomal recessive inheritance and four with maternal inheritance. In addition, two of six patients (33.3%) presenting with aminoglycoside-induced sensorineural hearing loss (SNHL) were associated with the A1555G mutation. All but one of the patients carrying the mutation showed high-frequency SNHL. Distortion-product levels of DPOAE were reduced to the noise levels, suggesting the A1555G mutation caused cochlear deafness. Cochlear microphonics in ECochG showed elevation of the detection thresholds and corresponding audiometric thresholds. The ECochG data implied that patients with high-frequency SNHL had impairment of the cochlear hair cells that was most severe toward the basal turn. The electronystagmographic findings indicated no apparent vestibular dysfunction. CONCLUSIONS: Screening for the A1555G mutation, even in patients with idiopathic bilateral SNHL, likely would be useful for preventing further development and/or acceleration of the deafness.

Comparison of duration of deafness and tumour invasion to the inner ear from metastatic tumours of the internal auditory canal: human temporal bone pathology.

Four cases (seven ears) of metastatic tumour of the internal auditory canal were studied. The histopathological findings confirmed that the inner ear invasion of the tumour follows a unique course, as reported in the literature. Relationship between duration of deafness and extent of tumour invasion in the inner ear is discussed. It is suggested that the deafness could occur via neural invasion or compression near the ductus spiralis foraminosus.