Endolymphatic sac tumor as a rare differential diagnosis of sudden idiopathic hearing loss.

We report on a 59-year-old patient who initially suffered a sudden left-sided hearing loss of 50-60 dB with tinnitus and presented to our department due to persistence. To exclude a retrocochlear pathology, an MRI and a CT of the temporal bone were performed externally. CT morphology revealed an osteolytic process of approximately 19x10x27mm in the left petrous bone retrolabyrinthine and retrocochlear involving the aqaeuductus vestibuli with destruction of the dorsal wall of the petrous bone. Transmastoidal exploration for a tissue sample was performed immediately. Histology revealed an adeonoid tumor compatible with an endolymphatic sac tumor (ELST). After discussion at our interdisciplinary tumor board, we performed a subtotal resection of with insertion of a cochlear implant dummy electrode. ELST is a rare aggressive and locally destructive growing tumor of the petrous bone. There is an association with Von Hippel-Lindau syndrome (VHL). 15% of patients with VHL develop ELST. After completion of adjuvant radiotherapy and gamma-knife radiosurgery, imaging and a re-biopsy were performed. Here most likely inactive residual tumor tissue could be detected. Tone audiogram showed functional deafness, so that cochlear implantation was offered to the patient. ELST is often clinically associated with progressive hearing loss, tinnitus, and vertigo. To limit progression, early diagnosis and resection of the tumor are crucial. Furthermore, for surgical procedures including a labyrinthectomy a simultaneous insertion of a cochlear implant dummy electrode is recommended to prevent possible fibrosis of the cochlea and to allow a two-stage hearing rehabilitation.

Publication History

Article published online:
24 May 2022