Endolymphatic hydrops is well known of the lay public in its primary form that is Ménière disease. Nowadays, the best w ay to approach it in vivo, is to use magnetic resonance imaging (MRI).

However, endolymphatic hydrops don't limit itself to its primary form but cover a whole range of pathologies.

The hypothesis is that patients with vestibular schwannomas are more likely to develop secondary saccular hydrops.

The aim is to compare high-resolution T2-weighted images of the saccule in patients followed up for vestibular schwannomas with healthy volunteers and histological sections from cadavers in order to identify its changes.

The secondary purpose of The protocol is to determine if vestibular and audiometric abnormalities could be related to this secondary hydrops more specifically than to the tumor size and localisation.

Inclusion Criteria:

• Age> 18,
• Subject having benefited from an MRI with T2 high-resolution 3D sequence (FIESA) in the context of the diagnosis of vestibular schwannoma between 2008 and 2017 at the University Hospitals of Strasbourg,
• Subject who has agreed to the use of medical data for the purposes of this research.

Exclusion Criteria:

• Refusal of the patient to participate in the study
• Insufficient imaging data,
• Tumors already treated,
• Atypical tumors with uncertain diagnosis, intra-labrinthic or intra-labyrinthine schwannomas, concomitant infectious or inflammatory pathology in the middle or inner ear.
• Impossibility of giving the subject informed information (difficulty understanding the subject,)
• Subject under the protection of justice
• Subject under guardianship or curatorship

Patient having benefited from an MRI with T2 high-resolution 3D sequence (FIESA) in the context of the diagnosis of vestibular schwannoma between 2008 and 2017 at the University Hospitals of Strasbourg,