Endolymphatic sac tumours (ELST) are very rare, locally invasive tumours of endolymphatic sac. Early detection of these tumours is critical, because early surgical intervention may prevent further hearing loss. Endolymphatic sac tumours do not metastasize, but are highly locally aggressive.
Typically endolymphatic sac tumours are encountered in young individuals, with a mean age at onset is 22 years 2.
Endolymphatic sac tumours typically present with the following symptoms and signs:
- hearing loss: 95%
- acute (43%)
- gradual (remainder)
- tinnitus: 92%
- vertigo or disequilibrium: 62%
- aural fullness: 29%
- facial paresis: 8%
These tumours are composed of two histological types:
- mixed type: generally confined
- papillary adenomatous type: more aggressive and often locally invades the temporal bone
Endolymphatic tumours are most often associated with von Hippel-Lindau disease (vHL) and are detected in 11-16% patients with vHL 2. However, in ~60% of patients with vHL and vestibulocochlear symptoms, there is no evidence on imaging of an endolymphatic sac tumour 2.
When these tumours are present in the setting of vHL, then 30% of tumours are bilateral 2.
Generally, endolymphatic sac tumours always arise from and involve the endolymphatic sac or duct.
- erosion of petrous bone in an infiltrative or "moth-eaten" pattern
- often intense enhancement
Signal characteristics include:
- T1: may show high-intensity
- T1 C+ (Gd): typically show enhancement in the non-cystic component of the tumour
- T2: often of heterogeneous signal
Treatment and prognosis
Surgical excision is the treatment of choice when possible 3.
History and etymology
It was first described in 1989 by Dennis K Heffner, an American physician 4. Earlier than this they were probably misdiagnosed as choroid plexus tumours, adenomas, and adenocarcinomas of posterior fossa or cerebellopontine angle.
Possible imaging differential considerations include:
glomus jugulare tumour
- centre of the lesion will be at the jugular bulb rather than the vestibular aqueduct
enlarged vestibular aqueduct
- expansion of aqueduct, with smooth margins
- normal shape of the aqueduct maintained
- located in the petrous air cells
- bone around the aqueduct is not usually aerated
- most often located in the petrous apex, not vestibular aqueduct
- hyperostotic underlying bone
- bony metastasis
- 1. Choyke PL, Glenn GM, Walther MM et-al. von Hippel-Lindau disease: genetic, clinical, and imaging features. Radiology. 1995;194 (3): 629-42. Radiology (abstract) - Pubmed citation
- 2. Lonser RR, Kim HJ, Butman JA et-al. Tumors of the endolymphatic sac in von Hippel-Lindau disease. N. Engl. J. Med. 2004;350 (24): 2481-6. doi:10.1056/NEJMoa040666 - Pubmed citation
- 3. Poletti AM, Dubey SP, Colombo G, Cugini G, Mazzoni A. Treatment of endolymphatic sac tumour (Papillary adenocarcinoma) of the temporal bone. (2016) Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology. 21 (4): 391-4. doi:10.1016/j.rpor.2015.06.003 - Pubmed
- 4. Heffner DK. Low-grade adenocarcinoma of probable endolymphatic sac origin A clinicopathologic study of 20 cases. (1989) Cancer. 64 (11): 2292-302. Pubmed
Inner ear pathology
inner ear anatomy
- enlarged vestibular aqueduct
- semicircular canal dysplasia
- classification of cochlear anomalies
- infection and inflammation
- trauma and miscellaneous