The local ethical committee approved the publication of this clinical case. A written informed consent form was collected from the patient.
1. Clinical and audiological evaluation
<ol>
	<li>Collect personal or familiar history of VHL disease or compatible symptoms from the patient.</li>
	<li>Perform a neurological examination to investigate central causes. Ensure that there is no pathological cause to be underlined and the facial nerve function is normal.</li>
	<li>Assess ex...

<ol>
	<li>Heffner, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-grade+adenocarcinoma+of+probable+endolymphatic+sac+origin+A+clinicopathologic+study+of+20+cases.">Low-grade adenocarcinoma of probable endolymphatic sac origin A clinicopathologic study of 20 cases.</a> Cancer. 64 (11), 2292-2302 (1989).</li><li>Lonser, R. R., Baggenstos, M., Kim, H. J., Butman, J. A., Vortmeyer, A. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+vestibular+aqueduct:+site+of+origin+of+endolymphatic+sac+tumors.">The vestibular aqueduct: site of origin of endolymphatic sac tumors.</a> J Neurosurg. 108 (4), 751-756 (2008).</li><li>Megerian, C. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endolymphatic+sac+tumors:+histopathologic+confirmation,+clinical+characterization,+and+implication+in+von+Hippel-Lindau+disease.">Endolymphatic sac tumors: histopathologic confirmation, clinical characterization, and implication in von Hippel-Lindau disease.</a> Laryngoscope. 105, 801-808 (1995).</li><li>Zanoletti, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endolymphatic+sac+tumour+in+von+Hippel-Lindau+disease:+management+strategies.">Endolymphatic sac tumour in von Hippel-Lindau disease: management strategies.</a> Acta Otorhinolaryngol Ital. 37 (5), 423-429 (2017).</li><li>Mendenhall, W. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+Treatment+of+Endolymphatic+Sac+Tumor+of+the+Temporal+Bone.">Current Treatment of Endolymphatic Sac Tumor of the Temporal Bone.</a> Adv Ther. 35 (7), 887-898 (2018).</li><li>Wu, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+management+of+endolymphatic+sac+tumor:+classification,+outcomes+and+strategy.+A+single+institution's+experience.">Surgical management of endolymphatic sac tumor: classification, outcomes and strategy. A single institution's experience.</a> Eur Arch Otorhinolaryngol. , (2022).</li><li>Bausch, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+endolymphatic+sac+tumors+and+von+Hippel-Lindau+disease+in+the+International+Endolymphatic+Sac+Tumor+Registry.">Characterization of endolymphatic sac tumors and von Hippel-Lindau disease in the International Endolymphatic Sac Tumor Registry.</a> Head Neck. 38, E673-E679 (2016).</li><li>Tang, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+Review+of+Endolymphatic+Sac+Tumor+Treatment+and+Outcomes.">Systematic Review of Endolymphatic Sac Tumor Treatment and Outcomes.</a> Otolaryngol Head Neck Surg. , (2022).</li><li>Balasubramaniam, S., Deshpande, R. B., Misra, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gamma+knife+radiosurgery+in+jugular+foramen+endolymphatic+sac+adenocarcinoma.">Gamma knife radiosurgery in jugular foramen endolymphatic sac adenocarcinoma.</a> J Clin Neurosci. 16 (5), 710-711 (2009).</li><li>Poletti, A. M., Dubey, S. P., Colombo, G., Cugini, G., Mazzoni, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+endolymphatic+sac+tumour+(Papillary+adenocarcinoma)+of+the+temporal+bone.">Treatment of endolymphatic sac tumour (Papillary adenocarcinoma) of the temporal bone.</a> Rep Pract Oncol Radiother. 21 (4), 391-394 (2016).</li><li>Bambakidis, N. C., Megerian, C. A., Ratcheson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+grading+of+endolymphatic+sac+tumor+extension+by+virtue+of+von+Hippel-Lindau+disease+status.">Differential grading of endolymphatic sac tumor extension by virtue of von Hippel-Lindau disease status.</a> Otol Neurotol. 25 (5), 773-781 (2004).</li><li>Schipper, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endolymphatic+sac+tumours:+surgical+management.">Endolymphatic sac tumours: surgical management.</a> J Otolaryngol. 35 (6), 387-394 (2006).</li><li>Li, F., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grading+system+and+surgical+approaches+for+endolymphatic+sac+tumors.">Grading system and surgical approaches for endolymphatic sac tumors.</a> Arch Otorhinolaryngol. 278 (5), 1345-1353 (2021).</li><li>Chittiboina, P., Lonser, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Von+Hippel-Lindau+disease.">Von Hippel-Lindau disease.</a> Handb Clin Neurol. 132, 139-156 (2015).</li><li>Sykopetrites, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+endolymphatic+sac+tumor:+challenges+in+the+eradication+of+a+localized+disease.">The endolymphatic sac tumor: challenges in the eradication of a localized disease.</a> Eur Arch Otorhinolaryngol. 278 (7), 2297-2304 (2021).</li><li>Devaney, K. O., Ferlito, A., Rinaldo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endolymphatic+sac+tumor+(low-grade+papillary+adenocarcinoma)+of+the+temporal+bone.">Endolymphatic sac tumor (low-grade papillary adenocarcinoma) of the temporal bone.</a> Acta Otolaryngol. 123 (9), 1022-1026 (2003).</li></ol>

The authors declare no conflicts of interest.

ELST are rare and locally aggressive neoplasms that arise on the posteromedial surface of the temporal bone. Due to their slow growth rate, and the initial paucity of the symptoms, the diagnosis is often delayed, resulting in an advanced tumor stage. Since the surgery morbidity as well as the oncologic outcomes are strongly correlated with the tumor dimensions and extension6,8,13,15, an early d...

Endolymphatic sac tumors (ELST) are neoplasms originating from the endolymphatic sac, a neuroectoderm-derived organ located in the posteromedial surface of the temporal bone. Histologically, ELST are characterizable as low-grade papillary adenocarcinoma1. Usually, ELST are slow-growing, with local aggressiveness and a low risk of distant metastases2,3,4. ELST can be sporadic, but they are also frequently associated with von Hippel Lindau disease (VHL)4.
Given the slow growing rate, the paucity of the clinical signs, and the late onset of the symptoms, they are difficult to diagnose in the early stages, especially when not associated with VHL5,6. The typical symptomatology at diagnosis of ELST includes hearing loss (79.8%), tinnitus (52.6%), and disequilibrium (45.5%), due to endolymphatic hydrops or intralabyrinthine hemorrhages4,7,8. Further and less frequent symptoms are facial palsy (25.6%), headache (13.8%), otalgia (5.1%), and trigeminal symptoms (3.2%)8.
The current treatment of ELST is primarily surgical resection. The tumor&#39;s residuals can be treated with stereotactic radiosurgery, which can be considered if the patient cannot tolerate the operation9,10. The surgical approach and the prognosis are mostly related to the tumor extension6. Even if there is no official staging system for ELST11,12, a recent grading system proposed by Li and colleagues13, based on imaging data and intraoperative findings, defined four main grades, according to the tumor extension. This and other previously proposed staging systems are reported in Table 1.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Article</td>
			<td colspan="4">ELST Staging / Grading</td>
		</tr>
		<tr>
			<td>Bambakidis et al.11</td>
			<td colspan="4">Stage I: confiled to the temporal bone and middle ear</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Stage II: extended to the posterior fossa</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Stage III: extended to the middle cranial fossa</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Stage IV: extended to the clivus and/or sphenoid wing</td>
		</tr>
		<tr>
			<td>Schipper et al.12</td>
			<td colspan="4">Type A: limited to the dura of the posterior cranial fossa</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Type B: infiltration of lateral semicircular canal and/or cochlea</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Type C: infiltration of sigmoid sinus and/or jugular bulb</td>
		</tr>
		<tr>
			<td>Li et al.13</td>
			<td colspan="4">Grade I: confined to the posterior petrous bone between posterior semicircular canal and posterior fossa, may involve facial nerve, no inner ear and jugular foramen invasion</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Grade II: extended anteriorly with invasion of semicircular canals, cochlea, IAC, middle ear, without cerebellopotine angle and jugular foramen involvement</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Grade IIIa: involvement of jugular foramen or internal carotid artery or clivus</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Grade IIIb: extensive intracranial invasion or involvement of cavernous sinus or jugular foramen</td>
		</tr>
		<tr>
			<td>Wu et al.6</td>
			<td colspan="4">Type I: confined to the endolymphatic sac region</td>
		</tr>
		<tr>
			<td></td>
			<td colspan="4">Type II: extended to at least another one anatomic structure</td>
		</tr>
	</tbody>
</table>
Table 1: Previously published tumor staging systems. An overview of previously published grading/staging systems.
To date, only ~300 cases were reported, mostly as single clinical cases or small case series5,6. Recurrence rates and survival estimates have not been clearly defined yet8. In the present paper, we report the clinical and surgical management of a single case of sporadic ELST, as well as the follow-up results, providing clinicians our experience of the handling of such a challenging otologic skull base surgery and rare disease. Here, we describe ELST in a 55-year-old woman who accessed our otologic tertiary level referral center from a peripheric hospital. The patient had been hospitalized 3 days before for a sudden worsening of the left hearing loss, which began 3 months earlier, accompanied by an episode of acute vertigo with nausea and vomiting. The anamnesis was positive for hypertension and hypercholesterolemia, both under treatment, and smoking (3 pack-years). No personal or familiar history of VHL disease or compatible symptoms were reported by the patient.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>AC40</td>
			<td>Interacoustic</td>
			<td></td>
			<td>Clinical audiometer</td>
		</tr>
		<tr>
			<td>AT235</td>
			<td>Interacoustic</td>
			<td></td>
			<td>Clinical tympanometry</td>
		</tr>
		<tr>
			<td>Innova 3131</td>
			<td>GE Healthcare</td>
			<td></td>
			<td>Biplane angiograph</td>
		</tr>
		<tr>
			<td>LightSpeed VCT</td>
			<td>GE Healthcare</td>
			<td></td>
			<td>64 Slice CT system</td>
		</tr>
		<tr>
			<td>S2 &#960;Drive</td>
			<td>Striker</td>
			<td></td>
			<td>Drilling system for Otosurgery</td>
		</tr>
		<tr>
			<td>Signa HDX</td>
			<td>GE Healthcare</td>
			<td></td>
			<td>1.5 T MRI system</td>
		</tr>
		<tr>
			<td>SYNAPSYS VNG</td>
			<td>Inventis</td>
			<td></td>
			<td>Video nystagmograph</td>
		</tr>
	</tbody>
</table>

surgical treatment of an endolymphatic sac tumor

Endolymphatic sac tumors (ELST) are low-grade papillary adenocarcinoma originating from the endolymphatic sac. Usually slow-growing, with local aggressiveness and a low risk of distant metastases, ELST can be sporadic but also frequently associated with von Hippel Lindau disease. The current treatment of ELST is primarily surgical resection. A 55-year-old woman accessed our otologic tertiary level referral center for a sudden worsening of hearing loss in her left ear and vertigo. A magnetic resonance (MRI) and computer tomography scan study subsequently showed a mass in the petrous bone; hence, the presence of an ELST was hypothesized. After embolization of the mass, the patient underwent surgical removal of the lesion. The resection of the mass was done through a translabirinthine approach, with an uneventful procedure. No residual disease remained after surgery. After 24 months of radiologic follow up with MRI, there are no signs of recurrence disease. This paper reports the management of this sporadic ELST, as well as the follow up results, providing clinicians this protocol for the handling of such a challenging otologic skull base surgery and rare disease.

From the audiologic assessment, it was possible to identify a moderately severe left sensorineural hearing loss (Figure 1), with a reduction of word discrimination. The tympanometry was bilaterally normal, and the stapedial reflexes were evocable with ipsilateral and contralateral stimulus. At the videonystagmography , it was possible to assess a grade II horizontal spontaneous nystagmus beating on the right side, which grew in intensity after head shaking. From the clinical and audiological...

Watch this Scientific Journal Video about Surgical Treatment of an Endolymphatic Sac Tumor at JoVE.com

Surgical Treatment of an Endolymphatic Sac Tumor

Here, we discuss clinical and radiological features of endolymphatic sac tumors and report the methodology and results of a surgical removal in a case in care at our otologic referral center.

Endolymphatic sac tumors (ELST) are low-grade papillary adenocarcinoma originating from the endolymphatic sac. Usually slow-growing, with local ...

This protocol is significant as it shows how to treat an endolymphatic sac tumor effectively. A prompt diagnosis based on the clinical picture and imaging assessment could lead to a manageable surgery for tumor removal. To begin, perform MRI examination using axial fluid-attenuated inversion recovery and axial fast spin echo T2-weighted sequences.Target steady-state free precession images with a fast imaging employing steady-state acquisition, or FIESTA, sequence on the inner ear. If a mass appears in the context of the petrous bone, perform a high-resolution computer tomography with at least 64-slice scan to confirm the diagnosis. Once the ELST is suspected, define the grading of the tumor and plan the surgical approach for the mass resection.After performing a coil embolization and resection of the mass, make a C-shaped retroauricular incision, and raise the flap of the temporalis muscle. Perform ample mastoidectomy with a Stryker S2 PiDrive drilling system, and cut the round precision fluted tips and the coarse and fine diamond round tips from the drilled structures. Expose the sigmoid sinus posteriorly and the dura of the middle cranial fossa superiorly.Complete an ample antrotomy with complete exposure of the small process of the incus. Then prepare a posterior tympanotomy by drilling out all the retrofacial mastoid cells up to the mastoid tip until the jugular bulb is identified. Complete the posterior labyrinthectomy by dissecting the semicircular canals.Dissect the posterior bony labyrinth until identification of the internal auditory canal. Next, cut the dura and remove it on block with the tumor to identify the neoplasm and completely remove the tumor. Conduct an intraoperative extemporaneous histological examination.Seal the posterior tympanotomy and the antrotomy with surgical wax, and fill the ample mastoid cavity with autologous abdominal fat and fibrin glue. From the audiologic assessment, it was possible to identify moderately severe left sensory neural hearing loss with reduced word discrimination. The left mastoid cells were occupied by high-intensity mucous material, causing a swollen appearance of the cortex bone and the posterior side of the petrous part with obliteration of the ipsilateral pontocerebellar cistern and minimal imprint on the left cerebellar gyri, consistent with the presence of an ELST.The high-resolution computer tomography of the petrous bone with a 64-slice scan confirmed the presence of an isodense mass on the posterior wall of the petrous bone with erosion in an infiltrative moth-eaten pattern. According to the Lee grading system, a grade 2 ELST was suspected. The diagnostic digital subtraction angiogram showed a vascular tumor with tumor blush due to blood supply from the left external carotid artery's ascending pharyngeal, posterior auricular, and occipital branches.The post-embolization angiogram showed complete obliteration of the tumor blush without any complications during and after the procedure. After a prompt diagnosis, a full resection of an endolymphatic sac tumor is doable, even if demanding. During the surgery, the most important point is to perform a very ample mastoidectomy, providing a full exposure of the posterior labyrinth and a good access to the endolymphatic sac region.

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452 Görüntüleme.  University of Pisa. Bu protokol, endolenfatik kese tümörünün etkili bir şekilde nasıl tedavi edileceğini göstermesi açısından önemlidir. Klinik tabloya ve görüntüleme değerlendirmesine dayalı hızlı bir tanı, tümörün çıkarılması için yönetilebilir bir ameliyata yol açabilir. Başlamak için, eksenel sıvı zayıflatılmış inversiyon geri kazanımı ve eksenel hızlı spin eko T2 ağırlıklı sekansları kullanarak MRI incelemesi yapın.İç kulakta kararlı durum edinimi ve...