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 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.
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'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.
Article | ELST Staging / Grading | |||
Bambakidis et al.11 | Stage I: confiled to the temporal bone and middle ear | |||
Stage II: extended to the posterior fossa | ||||
Stage III: extended to the middle cranial fossa | ||||
Stage IV: extended to the clivus and/or sphenoid wing | ||||
Schipper et al.12 | Type A: limited to the dura of the posterior cranial fossa | |||
Type B: infiltration of lateral semicircular canal and/or cochlea | ||||
Type C: infiltration of sigmoid sinus and/or jugular bulb | ||||
Li et al.13 | 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 | |||
Grade II: extended anteriorly with invasion of semicircular canals, cochlea, IAC, middle ear, without cerebellopotine angle and jugular foramen involvement | ||||
Grade IIIa: involvement of jugular foramen or internal carotid artery or clivus | ||||
Grade IIIb: extensive intracranial invasion or involvement of cavernous sinus or jugular foramen | ||||
Wu et al.6 | Type I: confined to the endolymphatic sac region | |||
Type II: extended to at least another one anatomic structure |
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.
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…
The authors have nothing to disclose.
None.
AC40 | Interacoustic | Clinical audiometer | |
AT235 | Interacoustic | Clinical tympanometry | |
Innova 3131 | GE Healthcare | Biplane angiograph | |
LightSpeed VCT | GE Healthcare | 64 Slice CT system | |
S2 πDrive | Striker | Drilling system for Otosurgery | |
Signa HDX | GE Healthcare | 1.5 T MRI system | |
SYNAPSYS VNG | Inventis | Video nystagmograph |