Petrous apex cholesterol granuloma: pictorial review of radiological considerations in diagnosis and surgical histopathology.

BACKGROUND: Petrous apex cholesterol granulomas are expansile, cystic lesions containing cholesterol crystals surrounded by foreign body giant cells, fibrous tissue reaction and chronic inflammation. Appropriate treatment relies on an accurate radiological diagnosis and an understanding of the distinguishing radiological features of relevant entities in the differential diagnosis of this condition. METHODS: Firstly, this paper presents a pictorial review of the relevant radiological features of petrous apex cholesterol granuloma, and highlights unique features relevant to the differential diagnosis. Secondly, it reviews the histopathological and radiological findings associated with surgical drainage of these lesions. RESULTS: Radiological features relevant to the differential diagnosis of petrous apex cholesterol granuloma are reviewed, together with radiological and histopathological features relevant to surgical management. Following surgical management, histopathological and radiological evidence demonstrates that the patency of the surgical drainage pathway is maintained. CONCLUSION: Accurate diagnosis of petrous apex cholesterol granuloma is essential in order to instigate appropriate treatment. Placement of a stent in the drainage pathway may help to maintain patency and decrease the likelihood of symptomatic recurrence.

Possible role of biofilm in fulminant meningitis related to cochlear implantation of dysplastic inner ear.

UNLABELLED: Thanks to improvements in device design and surgical procedures, the number of potential candidates for cochlear implantation has been growing to include patients with inner ear malformations. Many precautions are taken pre-, peri- and postoperatively for these patients given the increased risk of surgical and medical complications, but with the rising bacterial resistance to antibiotics and the discovery of biofilm as a probable cause of chronic infections, postoperative morbidity remains higher than desired. OBJECTIVE: The purpose of this investigation is to describe histological findings on a temporal bone from a 2-year-old infant with a cochlear implant and an inner ear deformity who died of bacterial meningitis. MATERIALS AND METHODS: The patient's temporal bone was studied under light microscopy, the cochlear implant studied with a scanning electron microscope, and later subjected to in situ hybridization to find bacterial DNA. RESULTS: The scanning electron microscopy image shows cellular formations on the surface of the implant, which later binds to the probe used for the in situ hybridization. CONCLUSION: There is evidence that bacterial DNA is present on the electrode array, which suggests existence of biofilm formation on the cochlear implant surface.

Cholesteatoma behind an intact tympanic membrane: histopathologic evidence for a tympanic membrane origin.

BACKGROUND: Several theories have been proposed with respect to the origin and pathogenesis of cholesteatoma behind an intact tympanic membrane. CASE REPORT: The authors describe a case of cholesteatoma behind an intact tympanic membrane in a 71-year-old man with a history of tympanic membrane retraction fixed to the incus without evidence of a perforation. The membrane eventually became detached, and remnants of keratinizing squamous epithelium were found on the incus. DISCUSSION: Mechanisms such as metaplasia, ectopic epidermis rests, or ingrowth of meatal epidermis have been proposed to explain the pathogenesis of cholesteatoma behind an intact tympanic membrane. These findings, based on temporal bone histopathology, support the role of an acquired epidermal rest. CONCLUSIONS: This case report provides evidence that cholesteatoma behind an intact tympanic membrane can be established from a resolved retraction of the pars tensa of the tympanic membrane.

Auditory perception in vestibular neurectomy subjects.

The auditory efferent nerve is a feedback pathway that originates in the brainstem and projects to the inner ear. Although the anatomy and physiology of efferents have been rather thoroughly described, their functional roles in auditory perception are still not clear. Here, we report data in six human subjects who had undergone vestibular neurectomy, during which their efferent nerves were also presumably severed. The surgery had alleviated these subjects' vertigo but also resulted in mild to moderate hearing loss. We designed our experiments with a focus on the possible role of efferents in anti-masking. Consistent with previous studies, we found little effects of vestibular neurectomy on pure-tone detection and discrimination in quiet. However, we noted several new findings in all subjects tested. Efferent section increased loudness sensation (one subject), reduced overshoot effect (five subjects), accentuated 'the midlevel hump' in forward masking (two subjects), and worsened intensity discrimination in noise (four subjects). Poorer speech in noise recognition was also observed in the surgery ear than the non-surgery ear in three out of four subjects tested, but this finding was confounded by hearing loss. The present results suggest an active role of efferents in auditory perception in noise.

Chronic otitis media: histopathological changes: a post mortem study on temporal bones.

The temporal bones of 4 deceased individuals, with concomitant chronic otitis media are studied. The various histopathological changes in the middle ear cleft are examined: suppuration, polyps, granulation tissue. The possibilities of spontaneous healing of a perforated TM and the indications of surgical treatment are discussed.

Cholesteatomatous otitis media: histopathological changes. A post mortem study on temporal bones.

The histopathological changes in the temporal bones of 3 deceased donors individuals with concomitant chronic cholesteatomatous otitis media have been studied. The different forms of cholesteatoma are analyzed: the primary congenital, the primary acquired and the secondary acquired. The different clinical relevance and the different therapeutic guidelines are discussed.

Cochlear implant. Histopathological guide to indications and contraindications: a post mortem study on temporal bones.

We have studied the temporal bones of 4 deceased donors, individuals one with cochlear saccular degeneration, another with Mondini dysplasia, another with an ossification of the basal turn of the cochlea and the round window, post meningitis and the fourth who was implanted 10 years before. The indications and contraindications for cochlear implant placement are discussed.

Acoustic neuromas and meningiomas. Histopathological aspect: a post mortem study on temporal bones.

The histopathological changes in the temporal bones of three deceased donors individuals, two with concomitant acoustic tumors and one with concomitant petroclival meningioma have been studied. The differences between neuromas and meningiomas are examined. The different clinical relevance and the different therapeutic guidelines are discussed.

Neurofibromatosis and brainstem implants: what to do?

The histopathological changes in the temporal bones of one donor individual deceased for complications of neurofibromatosis type 2 are studied. The different modalities of presentation of neurofibromatosis and the criteria for the differential diagnosis are presented. The possibilities of the auditory brainstem implants in this pathology are discussed.

Cholesterol granuloma of the petrous apex. A post mortem study on temporal bones.

Otitis media (OM) is an infection localized in the middle ear: mastoid, middle ear cavity, Eustachian tube. The classification of OM includes otitis media with effusion, otitis media without effusion, and chronic otitis media. A rare complication of chronic otitis is cholesterol granuloma of the petrous apex. It may develop in any aerated portion of the temporal bone but most commonly develops when a pathologic process obstruct the air cell tracts to the petrous apex preventing normal aeration.

Mutations in a novel cochlear gene cause DFNA9, a human nonsyndromic deafness with vestibular dysfunction.

DFNA9 is an autosomal dominant, nonsyndromic, progressive sensorineural hearing loss with vestibular pathology. Here we report three missense mutations in human COCH (previously described as Coch5b2), a novel cochlear gene, in three unrelated kindreds with DFNA9. All three residues mutated in DFNA9 are conserved in mouse and chicken Coch, and are found in a region containing four conserved cysteines with homology to a domain in factor C, a lipopolysaccharide-binding coagulation factor in Limulus polyphemus. COCH message, found at high levels in human cochlear and vestibular organs, occurs in the chicken inner ear in the regions of the auditory and vestibular nerve fibres, the neural and abneural limbs adjacent to the cochlear sensory epithelium and the stroma of the crista ampullaris of the vestibular labyrinth. These areas correspond to human inner ear structures which show histopathological findings of acidophilic ground substance in DFNA9 patients.

Cochlear implantation in common cavity malformations using a transmastoid labyrinthotomy approach.

The transmastoid facial recess approach has become the standard technique for cochlear implantation. Although this approach has been used for implantation in patients with common cavity deformities, it is not without increased risk to the facial nerve. Using a direct approach to the common cavity that circumvents the facial recess, we have successfully implanted four patients with common cavity deformities. An aberrant facial nerve in one patient would have precluded placement of the electrode array using standard cochlear implant techniques. As demonstrated in these four patients, the direct approach to the common cavity is an effective approach for placement of the electrode array, minimizes risk to the facial nerve, and may decrease the likelihood of postoperative cerebrospinal fluid leaks. Intraoperative video footage demonstrates the feasibility and facility of this approach in patients with common cavity deformities.

Marrow-mesenchyme connections in the fetal and newborn tympanum. A new entity.

Examinations of 41 human fetal, 8 infant, and 8 juvenile temporal bones prepared for light microscopic evaluation revealed direct connections between the hematopoietic bone marrow and the unresolved mesenchyme in the middle ear. The connections first appeared at 15 weeks of gestation and became bridged by fibrous tissue, in most cases, by the postpartum age of 10 months. Between 16 and 18 months after birth, the marrow-mesenchyme connections gradually disappeared. The areas in which the connections were most numerous were the anterior epitympanum, the sinus tympani medial to the stapedius muscle, and transitory bone that occupies the area that will become the aditus of the antrum. Immunohistochemical staining demonstrated the existence of mature leukocytes in these connections. These connections may help protect the middle ear against bacterial invasion during the postnatal period.

A five-generation family with late-onset progressive hereditary hearing impairment due to cochleosaccular degeneration.

Cochleosaccular dysplasia or degeneration (Scheibe degeneration) is considered the most common cause of profound congenital hearing impairment, and accounts for approximately 70% of cases 2 with hereditary deafness. A five-generation family with hereditary hearing impairment associated with cochleosaccular degeneration has recently been identified. The diagnosis of classical Scheibe degeneration was based on histopathological findings in the temporal bones of the proband, a 61-year-old profoundly deaf male. Auditory structures in the brainstem of the proband were also studied. Twenty-two members of the family were contacted for surveys and blood samples. Of these, 6 males and 2 females have hearing impairment. Complete audiological evaluation was done on 12 family members, and prior audiologic records of the proband and affected family members were available for study. Affected family members suffer a mild bilateral high-frequency hearing loss during childhood and adolescence, and progress to moderate-to-profound deafness in the second and third decades of life. The family is suitable for linkage analysis and does not map to previously reported loci harboring autosomal dominant, nonsyndromic hereditary hearing impairment genes. The genetic study of this family will be helpful in identifying the genes which, when mutated, result in Scheibe degeneration.

Mutational spectrum in the neurofibromatosis type 2 gene in sporadic and familial schwannomas.

Using a heteroduplex approach and direct sequencing, we have completed the screening of approximately 88% of the neurofibromatosis type 2 (NF2)-coding sequence of DNA extracted from 33 schwannomas from NF2 patients and from 29 patients with sporadic schwannomas. The extensive screening has resulted in the identification of 33 unique mutations. Similarly to other human genes, we have shown that the CpG sites are more highly mutable in the NF2 gene. The frequency, distribution, and types of mutations were shown to differ between the sporadic and familial tumors. The majority of the mutations resulted in protein truncation and were consistent with more severe phenotype, however three missense mutations were identified during this study and were all associated with milder manifestations of the disease.