Endolymphatic sac tumour

Endolymphatic sac tumours (ELST) are very rare, locally invasive tumours of endolymphatic sac. Early detection of ELST is critical, because early surgical intervention may prevent further hearing loss. ELSTs do not metastasise but are highly locally aggressive. 

Mean age at onset is 22 years.

ELSTs present with the following symptoms and signs:

  • hearing loss: 95 %, acute in 43% and stepwise in the second half
  • tinnitus: 92%
  • vertigo or disequilibrium: 62%
  • aural fullness: 29%
  • facial paresis: 8%

Composed of two histological types:

  • mixed type: generally confined
  • papillary adenomatous type: more aggressive and often locally invades the temporal bone
Associations

Most often associated with von Hippel-Lindau disease (vHL). ELSTs are detected in 11-16% patients with vHL ref. In almost 60% of patients with vHL and vestibulocochlear symptoms, there is no evidence on imaging of an endolymphatic sac tumour ref.  

30% of tumours in vHL patients are bilateral.

CT

When visible, it gives a picture of bone erosion and the "moth-eaten" petrous bone. ELSTs commonly enhance intensely on CT.

MRI

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

It was first described in 1989 by Heffner et al. Earlier than this they were probably misdiagnosed as choroid plexus tumours, adenomas, and adenocarcinomas of posterior fossa or cerebellopontine angle. 

Other tumours of the cerebellopontine angle and posterior fossa.


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Article Information

rID: 1286
Section: Pathology
Tags: cases, refs
Synonyms or Alternate Spellings:
  • Endolymphatic sac tumor
  • Endolymphatic sac tumour (ELST)
  • Papillary cystadenomatous tumour or temporal bone
  • Papillary adenomatous tumour or temporal bone

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