[Cavernous angiomas of the brain stem: auditory and vestibular manifestations]

To establish the correlation between the clinical manifestations of hearing and balance disturbance and the anatomical site within the pons of cavernous angiomas, and to describe their clinical features, and the findings on ABR and MRI.

Two clinical cases of cavernous angioma with cochlear and vestibular manifestations underwent audiometric evaluation, with VNG and ABR as well as CT and MRI scans.

Cavernous angiomas are rare (less than 2% of intra-cranial space-occupying lesions). Their most common topographical site is midline in the pons, and may give rise to symptoms in attacks (due to episodes of bleeding within the tumour) which may mimic symptoms of peripheral origin (sudden deafness, fluctuating hearing loss, Menière-like vertigo). There may be ectopic remnants of the embryonic blood vascular system. They may be associated with other malformations (intra-cerebral venous angiomas, cavernous angiomas at other sites). Their development is often by sudden progression which may be dramatic, and have accompanying neurological features. For investigating the hearing and balance, ABR is an excellent test, giving a typical picture of a retro-cochlear lesion that necessitates progression to MRI, the investigation of choice. This will demonstrate the typical rosette-like appearance with a heterogeneous T2 image (a less dense peripheral ring, with a denser central signal). There is no specific medical treatment for this condition, and surgery is indicated only exceptionally. There is a contraindication to anticoagulant therapy, to platelet-dispersing medication and to violent sports activities. Two cases of cavernous angioma are reported; one was more anteriorly situated, and had mainly vestibular features, and the other was more posterior near the floor of the IVth ventricule, with mainly auditory features. The correlation of the anatomical and clinical findings with those of the MRI are discussed, especially in relation to our understanding of the auditory and vestibular pathways within the brainstem (the auditory striae, the crossed auditory pathways and the nuclei of the corpus trapezoideum for the auditory effects, and the paramedian reticular nucleus and crossed inter-commissure pathways to the cerebellum and vestibular nuclei, together with the proximity of the direct midline vestibulo-spinal tract, for the vestibular effects).