Extra-axial Cerebellopontine Cavernoma Involving the CN VII/VIII Complex: One More Differential Diagnosis

Objective: Cavernomas are the most common vascular malformations (constituting 10–15%) in the central nervous system. They are commonly present in the supratentorial compartment (70–80%) and more often within the brain parenchyma. Cerebellopontine angle cavernomas are however very rare, and less than 10 have been reported in the literature, We present a case of an extra-axial cerebellopontine cavernoma, as well as a literature review on this interestingly-located vascular abnormality.

Design: Case report and literature review.

Patients: A 28-year-old woman presented with hearing loss, headaches, mild facial palsy, facial pain, and left-sided weakness. Her radiological imaging had demonstrated a left cerebellopontine extra-axial space occupying lesion which had been initially presumed to be a vestibular schwannoma.

Methods: Case report with histopathology images and literature review.

Results: The patient had an initial operation via the translabyrinthine approach, based on a radiological diagnosis of vestibular schwannoma but the lesion was subsequently found to be vascular in origin. She was then followed up at regular intervals. Due to radiological progression and two (2) bleeding episodes within a short interval, she had an excision of the lesion via a retrosigmoid approach (with intraoperative electrophysiological monitoring) 8 years after her first presentation. Intraoperatively, a cavernoma was noted in the cerebellopontine angle splaying the facial (CN VII) and vestibulocochlear (CN VIII) nerves, and adherent to the nerve complex.

Conclusion: Although cavernomata rarely occupy the cerebellopontine angle, they should be considered as worthy candidates when discussing the differential diagnoses of cerebellopontine angle space occupying lesions as they could present with similar features clinically and radiologically.