Endolymphatic sac tumor (ELST) is a very rare tumor arising from the epithelium of the endolymphatic sac. Pathologically, ELST shows papillary growth patterns with extensive bony and soft tissue destruction. ELST commonly shows symptoms of endolymphatic hydrops such as hearing loss, vertigo and tinnitus by blocking the endolymphatic duct. As the tumor enlarges, patients experience various symptoms that include multiple cranial nerve palsy. Ten to thirty percents of ELST are related to Von Hippel Lindau (VHL) diseases. Also, bilateral tumors can develop when a patient has VHL-related ELST. The goal of treatment for ELST is total tumor eradication. The type of surgical approach is chosen by the surgeon in consideration of the tumor grade and the hearing status of the patient. In this report, we present a patient with ELST who was successfully treated with the modified translabyrinthine approach. We have also reviewed relevant literatures.
Cranial Nerve Diseases ; Endolymphatic Duct ; Endolymphatic Hydrops ; Endolymphatic Sac ; Epithelium ; Hearing ; Hearing Loss ; Humans ; Tinnitus ; Vertigo

Endolymphatic sac tumor is rare, locally aggressive hypervascular tumor of papillary structure, arising from the endolymphatic duct or sac in the posterior petrous bone. We present four cases with this tumor. Two patients were male and the other two were female. Age of each patient was 15, 52, 58, and 67 years. Three patients presented with progressive hearing loss and sustained vertigo for months to years and another one was referred for the tumor detected in routine medical check-up. Preoperative embolization was performed in 3 patients. Complete excision of the tumor was achieved in all patients using translabyrinthine or retrosigmoid approach. Herein, we describe the clinical and radiographic features, surgical treatment and pathologic findings with a review of the literature.
Endolymphatic Duct ; Endolymphatic Sac ; Female ; Hearing Loss ; Humans ; Male ; Petrous Bone ; Vertigo

A large vestibular aqueduct, an isolated anomaly of temporal bone, is relatively rare and its association with sensorinerual hearing loss in childhood is known as the enlarged vestibular aqueduct syndrome. Using MRI, we found enlarged endolymphatic ducts and sacs in four ears of our two patients. Signal intensity of enlarged endolymphatic sac that is detected higher than that of CSF in Fluid Attenuated Inversion Recovery (FLAIR) image may indicate poor prognisis with respect to bone conduction threshold in pure tone audiogram.
Bone Conduction ; Ear ; Endolymphatic Duct ; Endolymphatic Sac ; Hearing Loss ; Humans ; Magnetic Resonance Imaging ; Temporal Bone ; Vestibular Aqueduct*

BACKGROUND AND OBJECTIVES: Although the role of aquaporin-2 (AQP2) in the kidney has been well defined, its role in the inner ear remains to be determined. The present study was to investigate the effect of water deprivation on the expression of AQP2 in the inner ear. MATERIALS AND METHOD: Healthy male guinea pigs weighing 250 g were used. The experimental group underwent water restriction and the control underwent water loading with sucrose-containing water for 3 days. Concentrations of plasma arginine-vasopressin (AVP) were determined and electrocochleography (ECoG) recordings were made. An RT-PCR, real-time PCR and Westernblotting analysis were used for quantitative analysis of AQP2 mRNA and AQP2 protein expression. Immunohistochemistry was also used to evaluate the distribution of AQP2 water channel proteins in the inner ear. RESULTS: AQP2 was mainly expressed in the epithelium of endolymphatic sac, spiral limbus, spiral ligament and stria vascularis of scala media. The concentrations of plasma AVP were 9.2+/- 0.8 pg/mL in the experimental group and 0.78+/-0.3 pg/mL in the control. The summation potential/ action potential (SP/AP) ratio in ECoG was markedly increased in the experimental group (0.55 in the experimental and 0.29 in the control). RT-PCR and real time PCR as well as Western blot analysis showed that the level of AQP2 mRNA and protein in the cochlea and endolymphactic sac of the water-deprived group was significantly higher than those in the control group. CONCLUSION: These data suggest that AQP2 is one of the important water channels in fluid homeostasis in the inner ear. Moreover, the volume of endolymphatic space can be increased via AVP-AQP2 system in response to water deprivation.
Action Potentials ; Animals ; Aquaporin 2 ; Aquaporins ; Arginine Vasopressin ; Audiometry, Evoked Response ; Blotting, Western ; Cochlea ; Cochlear Duct ; Ear, Inner ; Endolymphatic Hydrops ; Endolymphatic Sac ; Epithelium ; Guinea ; Guinea Pigs ; Homeostasis ; Humans ; Immunohistochemistry ; Kidney ; Male ; Plasma ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Spiral Ligament of Cochlea ; Stria Vascularis ; Water Deprivation

While data from animal models have shown endolymphatic hydrops to be developed following the obstruction of the endolymphatic duct, such connection has not yet been established in humans. This study reports on a case of hearing loss at low frequencies, tinnitus and aural fullness after removal of a clival oculomotor schwannoma via retrolabyrinthine approach that included resection of the endolymphatic duct. Commencement of a low salt diet and diuretic medication resulted in almost complete recovery of hearing, although some subtle tinnitus and aural fullness persisted. The clinical outcome supports the appearance of this case to be an evidence of initiation of endolymphatic hydrops due to resection of the endolymphatic duct.
Diet ; Endolymphatic Duct* ; Endolymphatic Hydrops* ; Hearing ; Hearing Loss ; Hearing Loss, Sensorineural ; Humans ; Models, Animal ; Neurilemmoma ; Skull Base Neoplasms ; Tinnitus

The enlarged vestibular aqueduct syndrome (EVAS) is a clinical disease causing anatomical abnormality of bony canal in the temporal bone containing endolymphatic duct and sac. It is also associated with progressive sensorineural hearing loss with an isolated enlarged vestibular aqueduct. Familial inheritance of enlarged vestibular aqueduct syndrome (FEVAS) is rare and the correct mode of inheritance is not yet discovered. We studied familial inheritance in EVAS by performing clinical, audiological, radiographic and chromosomal analyses, and found strong indications that FEVAS may be an autosomal recessive trait. Further study would be focused on genetic evaluation of FEVAS.
Endolymphatic Duct ; Extravehicular Activity ; Hearing Loss, Sensorineural ; Temporal Bone ; Vestibular Aqueduct* ; Wills

Adult ; Diagnostic Errors ; Endolymphatic Duct ; Female ; Humans ; Lymphocytes ; Lymphoma ; diagnosis ; Palatine Tonsil ; Polyps ; diagnosis

BACKGROUND AND OBJECTIVES: Secretory activity, particularly of antibacterial agents such as lysozyme and lactoferrin, is an important aspect of the mucosal defense mechanism. The development of these agents may have a direct bearing on the susceptibility of the mucosa to infection. The antibacterial secretory enzymes such as lysozymes and lactoferrins are found in various mucosal tissues, and it has been suggested that these enzymes contribut to the defense against local mucosal infection. Specifically, lysozyme and lactoferrin are important components of innate immunity against pathogens at mucosal surfaces. The purpose of this study is to identify the distribution and expression of lysozyme, lactoferrin in endolymphatic duct of rat. MATERIALS AND METHOD: Normal rats (129P3/J, 10 cases) were used for this study. The expression level and distribution of lysozyme mRNA were analyzed by RT-PCR and quantitative image analysis. RESULTS: The expression of lysozyme and lactoferrin mRNA in endolymphatic ducts of rats was compared by quantitative image analysis. The results indicate that the relative expression of lysozyme mRNA resulted as 2.5 times greater than that of lactoferrin mRNA. CONCLUSION: The distribution and expression of lysozyme and lactoferrin in the endolymphatic duct of rat were identified. The study suggests that innate immunity such as lysozyme and lactoferrin are important components of defense mechanisms along with mucociliary clearance. Additionally, the authors think that the activity of lysozymes is more effective than that of lactoferrin in the endolymphatic duct of rat.
Animals ; Anti-Bacterial Agents ; Defense Mechanisms ; Endolymphatic Duct ; Immunity, Innate ; Lactoferrin ; Mucociliary Clearance ; Mucous Membrane ; Muramidase ; Rats ; RNA, Messenger ; Ursidae

PURPOSE: To evaluate the CT and MRI findings of the large endolymphatic duct or sac syndrome (LEDS) and its associated anomalies, with clinical features. MATERIALS AND METHODS: We retrospectively reviewed the MR and CT images of 52 ears obtained from 26 patients with LEDS. We reviewed the clinical findings, audiology testing, and treatment results. The degree of hearing loss was classified from normal to profound, based on pure tone audiometry. The largest areas were measured at each endolymphatic duct and analyzed to determine whether a correlation exists with the degree of hearing loss. We also analyzed the differences in measurements between CT and MRI findings. RESULTS: All 26 patients had some degree of sensorineural hearing loss, which resulted in 18 ears to undergo a cochlear implantation. One patient was diagnosed with Cornelia de Lange syndrome. Five patients had a sudden hearing loss onset. Ten ears had incomplete cochlear partitions, whereas 28 ears had enlarged vestibules. All patients had severe to profound hearing loss. We found no statistical correlation between the size of the largest area of the endolymphatic duct and the degree of hearing loss. The mean area of the endolymphatic ducts, as per an MRI examination, revealed slightly greater areas than the CT findings, although the differences were not significant. CONCLUSION: Enlarged vestibules and incomplete partitions of the cochlea were common anomalies associated with LEDS. We found no statistical correlation between the largest area of the endolymphatic duct or sac with the degree of hearing loss.
Audiology ; Audiometry ; Cochlea ; Cochlear Implantation ; Cochlear Implants ; De Lange Syndrome ; Ear ; Ear, Inner ; Endolymphatic Duct ; Hearing Loss ; Hearing Loss, Sensorineural ; Hearing Loss, Sudden ; Humans ; Retrospective Studies

Endolymphatic hydrops (EH) represents a histopathologic finding in which the structures bounding the endolymphatic space are distended by an enlargement of endolymphatic volume. EH primarily involves the cochlear duct and saccule but can involve the utricle and ampullae of the semicircular canals. EH is a consistent finding in patients with Meniere's disease, however, the reverse is not true. EH may occur as a consequence of a variety of disorders, including DFNA 9, Alport syndrome, serous labyrinthitis, suppurative labyrinthitis, otosyphilis, temporal bone fracture, surgical trauma, neoplasm, immune disorders, otosclerosis, or Paget's disease. The mechanism of development of hydrops is also unclear. This review provides information to understand the recent pathophysiologic mechanism and causal disoders in EH.
Cochlear Duct ; Ear, Inner ; Edema ; Endolymphatic Hydrops ; Humans ; Immune System Diseases ; Labyrinthitis ; Meniere Disease ; Nephritis, Hereditary ; Otosclerosis ; Saccule and Utricle ; Semicircular Canals ; Temporal Bone