A Narrow Internal Auditory Canal with Duplication in a Patient with Congenital Sensorineural Hearing Loss

A narrow internal auditory canal (IAC) with duplication is a rare anomaly of the temporal bone. It is associated with congenital sensorineural hearing loss. Aplasia or hypoplasia of the vestibulocochlear nerve may cause the hearing loss. We present an unusual case of an isolated narrow IAC with duplication that was detected by a CT scan. In this case, the IAC was divided by a bony septum into an empty stenotic inferoposterior portion and a large anterosuperior portion containing the facial nerve that was clearly delineated on MRI

Petrous Apex Cholesterol Granuloma Presenting as Endolymphatic Hydrops: A Case Report

A petrous apex cholesterol granuloma (PACG) is the most common lesion of the petrous apex mass. Affected patients present with various symptoms such as hearing loss, vertigo, headache, tinnitus, facial spasms, and diplopia. We report the case of a 32-yr-old man with a PACG, who was first misdiagnosed with Ménière's disease. He was placed on a low-salt diet, and prescribed medication from another hospital, for several months, but the symptoms persisted and worsened. The patient presented to the emergency room complaining of left facial twitching and numbness. To rule out a central neurological lesion, temporal bone magnetic resonance imaging was carried out and a 2.5 cm mass with high signal intensity on T1- and T2-weighted imaging, without gadolinium enhancement, was found. Because of the hearing and facial problems, we drained cholesterol-bearing material via an infralabyrinthine approach using a computer aided image-guided surgical device, the BrainLAB®. After the operation, the vertigo and hearing loss were no longer present. It is likely that the patent's Ménière's disease-like symptoms were due to the compression of the endolymphatic sac by a PACG

Cholesterol Granuloma of the Tympanic Membrane Presenting as a Blue Eardrum

Intramembranous tympanic membrane cholesterol granuloma (CG) occurs infrequently. Here, the authors report a case of CG in the tympanic membrane presenting as a blue eardrum in the right ear. In addition, a pinhole perforation noted in the anterosuperior area revealed a brown discharge. High-resolution temporal bone CT showed a bulging mass shadow in the middle ear and a soft tissue dense lesion that filled both the epitympanum and mastoid cavity. Tympanomastoidectomy was performed under general anesthesia. New bone formation was confirmed in the mastoid antrum and epitympanum, and the epitympanum was blocked by new bone. The tympanic membrane revealed a round, brownish mass with a glistening surface and a severely thickened pars tensa. We herein report this case and review pertinent medical literature

Cholesterol granuloma presenting as a mass obstructing the external ear canal

<p>Abstract</p> <p>Background</p> <p>Cholesterol granuloma (CG) may involve the middle ear, the mastoid bone and the petrous apex. However, CG presenting as a mass obstructing the external ear canal (EEC) is relatively rare and it can be a diagnostic challenge.</p> <p>Case Presentation</p> <p>We report a case of a CG occupying the mastoid antrum and presenting as a mass into the EEC. Temporal bone computerized tomography showed a soft tissue mass which eroded the posterior-superior bony wall of the EEC. On magnetic resonance imaging, the mass revealed a high signal on both T1 and T2-weighted images. The CG was removed by a mastoidectomy procedure and the histopathologic report confirmed the diagnosis of CG. A type III tympanoplasty was performed.</p> <p>Conclusions</p> <p>The postoperative course was uneventful.</p

Defects in vestibular sensory epithelia and innervation in mice with loss of Chd7 function: Implications for human CHARGE syndrome

CHD7 is a chromodomain gene mutated in CHARGE syndrome, a multiple anomaly condition characterized by ocular c oloboma, h eart defects, a tresia of the choanae, r etarded growth and development, g enital hypoplasia, and e ar defects including deafness and semicircular canal dysgenesis. Mice with heterozygous Chd7 deficiency have circling behavior and semicircular canal defects and are an excellent animal model for exploring the pathogenesis of CHARGE features. Inner ear vestibular defects have been characterized in heterozygous Chd7 -deficient embryos and early postnatal mice, but it is not known whether vestibular defects persist throughout adulthood in Chd7 -deficient mice or whether the vestibular sensory epithelia and their associated innervation and function are intact. Here we describe a detailed analysis of inner ear vestibular structures in mature mice that are heterozygous for a Chd7 -deficient, gene-trapped allele ( Chd7 Gt/+ ). Chd7 Gt/+ mice display variable asymmetric lateral and posterior semicircular canal malformations, as well as defects in vestibular sensory epithelial innervation despite the presence of intact hair cells in the target organs. These observations have important functional implications for understanding the clinical manifestations of CHD7 mutations in humans and for designing therapies to treat inner ear vestibular dysfunction. J. Comp. Neurol. 504:519–532, 2007. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56115/1/21460_ftp.pd

Variable expressivity of FGF3 mutations associated with deafness and LAMM syndrome

<p>Abstract</p> <p>Background</p> <p>Recessive mutations of fibroblast growth factor 3 (FGF3) can cause LAMM syndrome (OMIM 610706), characterized by fully penetrant complete labyrinthine aplasia, microtia and microdontia.</p> <p>Methods</p> <p>We performed a prospective molecular genetic and clinical study of families segregating hearing loss linked to <it>FGF3 </it>mutations. Ten affected individuals from three large Pakistani families segregating <it>FGF3 </it>mutations were imaged with CT, MRI, or both to detect inner ear abnormalities. We also modeled the three dimensional structure of FGF3 to better understand the structural consequences of the three missense mutations.</p> <p>Results</p> <p>Two families segregated reported mutations (p.R104X and p.R95W) and one family segregated a novel mutation (p.R132GfsX26) of <it>FGF3</it>. All individuals homozygous for p.R104X or p.R132GfsX26 had fully penetrant features of LAMM syndrome. However, recessive p.R95W mutations were associated with nearly normal looking auricles and variable inner ear structural phenotypes, similar to that reported for a Somali family also segregating p.R95W. This suggests that the mild phenotype is not entirely due to genetic background. Molecular modeling result suggests a less drastic effect of p.R95W on FGF3 function compared with known missense mutations detected in fully penetrant LAMM syndrome. Since we detected significant intrafamilial variability of the inner ear structural phenotype in the family segregating p.R95W, we also sequenced <it>FGF10 </it>as a likely candidate for a modifier. However, we did not find any sequence variation, pointing out that a larger sample size will be needed to map and identify a modifier. We also observed a mild to moderate bilateral conductive hearing loss in three carriers of p.R95W, suggesting either a semi-dominant effect of this mutant allele of <it>FGF3</it>, otitis media, or a consequence of genetic background in these three family members.</p> <p>Conclusions</p> <p>We noted a less prominent dental and external ear phenotype in association with the homozygous p.R95W. Therefore, we conclude that the manifestations of recessive <it>FGF3 </it>mutations range from fully penetrant LAMM syndrome to deafness with residual inner ear structures and, by extension, with minimal syndromic features, an observation with implications for cochlear implantation candidacy.</p