T1 MRI Gad positve intralabyrinthine non schwannoma mass

Intralabyrinthine schwannomas (ILS) are benign neoplasms originating from the peripheral branches of the cochlear nerve or vestibular nerve. As a differential diagnosis of cochleovestibular disorders and due to the good detectability on suitable magnetic resonance imaging (MRI) examinations, they have attained a special significance. The characteristic MRI finding of intralabyrinthine schwannomas is the enhancement of gadolinium in the T1- sequence and diminishing of the fluid signal in the T2- sequence.

In this report, we describe a 55-year-old man with a unilateral profound sensorineural hearing loss. In the MRI of the cerebellopontine angle, a cochlear and vestibulum enhancement in the T1- Gad sequence cochlea was observed, which indicated ILS. Basal turn and first turn cochleostomy and a labyrinthectomy in addition to a cochlear implantation revealed a mass that fills the vestibule and prolapses into the footplate and fills the basal turn. However, the histopathological examination showed no evidence of clinically suspected schwannoma, but fibrosed mucosa tissue with an increased inflammatory cell infiltrate with negative schwannoma immunology. To the best of our knowledge, this is the first report that describes a T1 Gad positive but schwannoma negative case. Magnetic resonance imaging and the management of this situation are discussed in this case report.

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Publication History

Article published online:
10 June 2020