An unusual middle-ear mass.

OBJECTIVE: We describe a case of endolymphatic sac tumour confined to the middle ear, which radiologically mimicked a glomus tympanicum, in a 58-year-old woman with tinnitus. CASE REPORT: A 58-year-old woman presented with a one-year history of right-sided tinnitus. The clinical, radiological and surgical features were felt to be in keeping with a glomus tympanicum. However, the histopathological picture was that of a low grade papillary carcinoma of the endolymphatic sac, i.e. an endolymphatic sac tumour.
CONCLUSION: Endolymphatic sac tumours are classically locally aggressive and centred around the petrous temporal bone. Further growth results in complete replacement of the mastoid and petrous pyramid by tumour. To the best of our knowledge, there have been no previous reports of an endolymphatic sac tumour located solely within the hypo- and epitympanum of the middle ear.