Immunohistochemical characterization of the human endolymphatic sac and its associated cell populations

Efficacy of Resection of Lateral Wall of Endolymphatic Sac for Treatment of Meniere's Disease

Background

To explore the long-term efficacy and safety of resection of the lateral wall of the endolymphatic sac for the treatment of intractable Meniere's disease (MD) as an alternative surgical procedure for treating this disorder.

Methods

Data from 73 patients who were referred to our hospital and diagnosed with unilateral MD between January 2015 and June 2019 were retrospectively analyzed in this study. Seventy-three patients who had frequent vertigo even after receiving standardized conservative treatment for at least half a year underwent resection of the lateral wall of the endolymphatic sac. Vertigo control and auditory function were assessed. Pure tone audiometry, caloric test, and vestibular evoked myogenic potential were performed to evaluate audiological and vestibular functions. The post-operative follow-up duration was more than 2 years.

Results

Among the 73 patients (male 34 cases, female 39 cases; age 20–69 years, average 51.4), vertigo was controlled effectively for 66 cases (90.4%) after 2 years of follow-up; 45 cases (61.6%) were completely controlled, and 21 cases (28.8%) were substantially controlled in this study. The patients of 16.4% had hearing loss with more than 10 dB change based on the four-tone average (0.5, 1, 2 and 3 kHz). No patient had a facial nerve weakness, cerebrospinal fluid leakage, or other complications.

Conclusion

Resection of the lateral wall of the endolymphatic sac, which can effectively control vertiginous symptoms in intractable MD patients, represents an effective and safe therapy for this disease. Resection of the lateral wall of the endolymphatic sac is expected to be used as an alternative treatment for MD.

A comparison of endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in reversing endolymphatic hydrops in Meniere's disease

Background

To explore the differences between endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in the reversal of endolymphatic hydrops (EH) in patients with intractable Meniere’s disease (MD).

Methods

A total of 27 MD patients receiving endolymphatic duct blockage surgery (n = 10), endolymphatic sac drainage surgery (n = 9) and endolymphatic sac decompression surgery (n = 8) underwent gadolinium-enhanced inner ear magnetic resonance imaging (MRI) scans prior to, 2 weeks after and at > 12 months following surgery.

Results

In the group with endolymphatic duct blockage, the second MRI revealed no changes in EH, whereas the third MRI revealed a reversal of vestibular EH in 3 patients and a downgrading of cochlear hydrops in 2 of these 3 patients, who presented with an improvement in their hearing and complete control of vertigo. In the group with endolymphatic sac drainage, the second MRI showed a reversal of EH in 4 patients, and no changes in EH in the remaining 5 patients, whereas the third MRI showed that those 4 patients who presented with a reversal of EH at the second MRI stage remained unchanged except a recurrence of vestibular hydrops in 1 patient. All 4 patients exhibited a complete control of vertigo, but hearing improved in 1, worsened in 1 and remained unchanged in 2. In the group with endolymphatic sac decompression, both the second and third MRI examination revealed no reversal of EH.

Conclusions

The present study has shown that both endolymphatic duct blockage surgery and endolymphatic sac drainage surgery have the potential to reduce EH in certain MD patients, but none of the patients receiving endolymphatic sac decompression surgery showed reversal of their EH.

Graphical Abstract

Dynamics in Endolymphatic Hydrops & Symptoms in Meniere's Disease After Endolymphatic Duct Blockage, Preliminary Results

Objective: The purpose of the present study was to evaluate the dynamics of endolymphatic hydrops (EH) and symptoms in a group of patients who underwent endolymphatic duct blockage (EDB) for treatment of intractable Meniere's Disease (MD), and to explore a metric for verifying the effectiveness of EDB procedure.

Methods: A total of 22 patients with intractable MD patients who underwent EDB participated in the present study. EH was visualized using locally enhanced inner ear magnetic resonance imaging (MRI) prior to and following surgery. The vestibular hydrops ratio (VHR) in the second MRI examination was compared with the pre-surgery recordings.

Results: Following EDB, 6 patients exhibited complete or partial reversal of EH, complete control of vertigo spells and reported improvement in hearing; 13 patients showed no changes in EH or hearing, but 5 of these patients exhibited complete control of vertigo attacks, and the other 8 patients exhibited improved control of vertigo attacks. The final 3 patients showed an increase in EH, but symptomatic worsening in 2 patients, and symptomatic improvement in 1 patient. There was a significant difference in the average VHR prior to and following EDB. Postoperative VHR was positively correlated with the frequency of vertigo spells in the latest 6 months of follow-up and improvement of postoperative average hearing threshold.

Conclusion: The decreased EH accompanying the reduction in vertigo attacks and hearing preservation may provide a metric for verifying the effectiveness of EDB treatment in patients with MD.

A rare case of endolymphatic sac tumour: clinicopathologic study and surgical management

Objective. Endolymphatic sac tumor (ELST) is a rare neoplasm arising from the intrapetrous portion of the endolymphatic sac, either isolated or in association with the von Hippel-Lindau disease. We report a sporadic case of ELST with an overview of the literature and a discussion of clinic-radiological, histopathologic, and surgical findings. Case Report. A young woman presented with a progressive hearing loss in the left ear. Otoscopy showed a reddish, bleeding hypotympanic mass. CT demonstrated an expansile lytic mastoid lesion extending to the middle ear, with bone erosion. MRI confirmed a lesion of increased signal on T1-weighted sequences. The patient underwent a canal wall-down tympanoplasty with complete removal of the tumor. Histopathology was consistent with a papillary ELST. Immunohistochemistry was positive for cytokeratin and chromogranin A. Conclusion. This paper highlights the rarity of ELST, the need for an accurate neuroradiological and immunohistochemical study at the early stages, and the timeliness of surgical treatment.

Experimental hyperactivity of the endolymphatic sac

Injury to the endolymphatic sac may play an important role in the pathogenesis of Ménière's disease, an inner ear disorder characterized by hearing loss, tinnitus and attacks of vertigo. Isoimmunization of 16 inbred Lewis rats with a crude endolymphatic sac extract and complete Freund's adjuvant induced hyperactivity of the endolymphatic sac. One group of rats was immunized by a single dose whereas a second group was immunized twice. Control animals were injected with Freund's adjuvant in saline only. Serum was collected from all rats by the end of the study and harvested autoantibodies were tested by immunohistochemistry. The endolymphatic sacs were investigated by transmission electron microscopy. Endolymphatic sac stimulation was observed in all immunized rats. Based on detailed ultrastructural observations, the degree of reactivity seemed proportional to the number of injections and the extent of immunization. Moreover, the ribosome-rich cells seemed hyperactive with an extravagant content of intracellular components: numerous rough endoplasmic reticulum and free ribosomes, morphological signs of extensive endo- and exocytosis, vesicles of material with a density similar to the homogeneous substance of which many were observed to fuse with primary lysozymes. Basolateral foldings were numerous and in the subepithelial capillaries formation of multiple and apposing fenestrations were observed. No endolymphatic sac stimulation was observed in the control animals. Specific ribosome-rich cell alterations identical to those present in the endolymphatic sac of Ménière's disease were observed 21 days after the first immunization. The observations suggest that either an autoantigen or a trophic factor, capable of inducing a hyperactivity of the ribosome-rich cells and an imbalance of the homogeneous substance metabolism, exists in the endolymphatic sac of the rat.

Papillary tumor of the temporal bone

Papillary tumors of the middle and inner ear have been interpreted histogenetically in many ways. In 1989 Heffner proposed the endolymphatic sac epithelium as a possible origin. These rare tumors are clinically aggressive and can cause extensive temporal bone destruction. Because of this behavior, endolymphatic sac tumors (ELST) were classified as low-grade adenocarcinomas, although metastasis has not yet been documented. Two papillary neoplasms of the temporal bone are presented, which we believe are examples of adenomatous tumors arising from the epithelium of the endolymphatic sac. One was associated with a pituitary adenoma. A third case of a papillary middle ear neoplasm is described that shows histologic features similar to the other two, but it was located in the tympanum and had no connection to the endolymphatic sac. This report focuses on clinical, radiologic, and histologic findings of papillary tumors of the temporal bone with additional emphasis on modern concepts of histogenesis and aspects of differential diagnosis.

Endolymphatic Sac Tumor: A Report of 3 Cases and Discussion of Management

Patients with an endolymphatic sac tumor (ELST) typically present with palsy of cranial nerves VII and/or VIII; other presenting symptoms include hearing loss, otalgia, occipital headaches, cranial nerve palsies, vertigo, gait ataxia, tinnitus, and otorrhea. ELSTs are extremely vascular, and they can invade and destroy temporal bone. Because of these characteristics, they are often mistaken for glomus tumors of the skull base. We describe the clinical presentation, evaluation, and management of ELSTs based on our review of the limited literature and our experience with 3 adults who presented to our tertiary care referral center with large ELSTs. Although these patients presented late in the course of their disease, their symptoms were relatively minor. Preoperative tumor embolization was performed, and a near-complete resection was achieved via an extended transotic approach in all 3 patients. The facial nerve was preserved without transposition in the first patient, the second patient underwent a primary nerve anastomosis, and the third required a cable graft of the facial nerve. Postoperative radiation therapy was administered to 2 of these patients. Follow-up by MRI detected no evidence of recurrence in any of the 3 patients.

Sensorineural hearing loss in chronic otitis media

OBJECTIVE

To determine whether chronic suppurative otitis media may cause sensorineural hearing loss.

METHODS

The files of 121 patients with unilateral chronic suppurative otitis media were reviewed in a retrospective study. Air conduction and bone conduction threshold averages were calculated over the speech frequencies (500 Hz, 1,000 Hz, and 2,000 Hz). Thresholds at 4 kHz were examined separately but in a similar way. Multiple linear regression models were used to clarify the relationships between sensorineural hearing loss and chronic otitis media.

RESULTS

Chronic suppurative otitis media was seen to be associated with sensorineural hearing loss. When age and normal side were corrected for, pure-tone threshold and bone conduction threshold at either the speech frequencies or at 4 kHz increased gradually according to the duration of the chronic suppurative otitis media. The threshold shift was more accentuated as age increased. The sensorineural hearing loss at 4 kHz seemed to be higher than that at the speech frequencies.

CONCLUSIONS

The inner ear is vulnerable against chronic suppurative otitis media. Older age increases this vulnerability. The proximity of the sensory cells to the potential source of harm (inflamed middle ear) may mean higher exposure, as reflected by the fact that sensory cells processing higher frequencies are more seriously damaged.

Antigen retrieval immunohistochemistry used for routinely processed celloidin-embedded human temporal bone sections: standardization and development

The use of immunohistochemistry (IHC) in routinely processed celloidin-embedded human temporal bone section has created a fruitful field in understanding the pathogenesis and pathophysiology of the human inner ear at a molecular level since the early 1990s when the antigen retrieval (AR) technique was developed. This review article focuses on several critical technical issues of AR technique based predominantly on our experiences and suggestions concerning further development and standardization of AR-IHC for IHC study of human temporal bone section, as well as other tissues embedded in celloidin. Examples of using AR-IHC in human temporal bone sections collected include our unpublished data in order to indicate the potential utility of this novel method. Suggestions of further development of AR techniques are proposed for references and comments.

Should endolymphatic sac tumors be considered part of the von Hippel-Lindau complex? Pathology case report

OBJECTIVE

Von Hippel-Lindau (vHL) disease is an inherited disorder characterized by numerous cystic and solid neoplasms. Because of the recent identification of the vHL gene, other investigators have demonstrated genetic mutations in this gene in several of the neoplasms associated with the disease. We describe a patient with an endolymphatic sac (ELS) tumor and vHL disease. The purpose of this study was to identify a similar genetic mutation within the vHL gene of the ELS tumor.

METHODS

Using the patient's archival pathological slides, neoplastic cells were microdissected to yield a purely neoplastic cell population. The deoxyribonucleic acid of these cells was then extracted and amplified via polymerase chain reaction. After sufficient amplification, the specimen was analyzed on a single-strand conformation polymorphism gel system to detect putative changes in the base sequence.

RESULTS

Single-strand conformation polymorphism gel system analysis yielded two bands representing the two single strands of deoxyribonucleic acid that were amplified. The upper band of the specimen was shifted down (compared with controls), representing a conformational change as a result of genetic mutation.

CONCLUSION

ELS tumors are uncommon, and, to our knowledge, only seven cases associated with vHL disease have been reported in the literature. Although this association has been previously mentioned, no definitive studies have linked the two together. We report the eighth case of ELS tumor and vHL disease. We have demonstrated through molecular biological techniques, that, in our patient's tumor, a genetic mutation occurred, and that this mutation is similar to mutations previously reported in other neoplasms associated with vHL. We therefore suggest that ELS tumors be considered among the neoplasms associated with vHL.

Aggressive papillary tumors of the temporal bone: an immunohistochemical analysis in tissue culture

Aggressive papillary tumors of the temporal bone are neoplasms that are locally invasive and destructive. Previously classified on histologic study as middle ear adenomas or adenocarcinomas, observational evidence suggested that they arose from endolymphatic sac. To evaluate this hypothesis, we established a tissue culture from cells derived from such a papillary tumor and compared immunohistochemical stains of the original tumor with stains on endolymphatic epithelium. Similarities in expression of neuroectodermal antigens were observed. Similar staining antigens in cells derived from tumor and the endolymphatic sac provide evidence that epithelium from endolymphatic sac is the site of origin for these aggressive neoplasms. In tissue culture the cells remain contact inhibited and dependent on serum or growth factors with survival beyond the expected senescence at 30 to 50 generations. Therefore the cell culture technique provides a model for study of the disruption of growth control and invasive properties of this tumor.

The significance of the human endolymphatic sac and its possible role in Menière's disease

Modern immunohistochemical methods allow a functional characterization of the human endolymphatic sac (ES) and its associated cell populations. The currently available immunohistochemical data of the extraosseous part of the human ES support the assumption that the epithelium is metabolically active and capable of both secretion and adsorption. The reactivity of the epithelial cells with antibodies against neuroendocrine antigens imply a paracrine activity of the human ES. Further results provide evidence for a possible role of the human ES in inner ear immune defence and indicate a putative functional relationship of the human ES to the common mucosa-associated immune system (MALT).

A study of neurotransmitters in human inner ear. Preservation of human temporal bone and value of organ donation for inner ear research

Twenty-nine human temporal bones (TBs) from 3 different groups of patients were used to investigate an effective preservation method of the inner ear and to study the suitability of TBs from organ donors for human inner ear research. Inner ears were fixed by perilymphatic perfusion and immersion fixation. Choline acetyltransferase (ChAT) and gamma-aminobutyric acid (GABA) activities were detected either by an indirect immunostaining method or by the peroxidase-anti-peroxidase (PAP) technique. The results show that the cytoarchitecture of the sensory epithelia is excellently preserved in specimens fixed within 2 h after death. ChAT- and GABA-immunoreactivities were revealed in the efferent nerve endings and fibers of the cochlea. Morphological preservation of the sensory epithelia was also good in specimens fixed within 5 h after death. However, inner ear sensory epithelia of organ donors that had died from head trauma and were in the definite brain death state for at least 7 1/2 h were severely damaged and showed cellular debris due to autolysis, although they were fixed within 2 1/2 h after death. The mechanisms underlying this damage of the sensory epithelia are discussed.

Papillary neoplasms (Heffner's tumors) of the endolymphatic sac

The sources of adenomatous neoplasms in the temporal bones are usually metastases or direct extensions from extratemporal lesions, or primary from the middle ear cleft. In 1989, Heffner added the endolymphatic sac's epithelium as another possible generative origin. In contrast to the adenomatous tumors of the middle ear or mastoid, the papillary cystic neoplasms of the endolymphatic sac are large and locally aggressive and often involve the middle and posterior cranial fossae and bone. These biologically low-grade adenocarcinomas have not been shown to be able to metastasize.