Cerebellopontine angle lipoma: case report and review of the literature.

Intracranial lipomas located in the cerebellopontine angle are extremely rare. These tumours are mal-developmental lesions which can cause slowly progressive neurological symptoms. The clinical management of these tumours differs significantly from other lesions in this region. A 27 year old woman presented with a 2-month history of vertigo and a slowly progressive deterioration of hearing in the left ear. Computed tomography (CT) revealed a large low-density mass in the left cerebellopontine angle without any contrast-enhancement. In T1-weighted magnetic resonance imaging (MRI) the lesion was hyper-intense and did not enhance after application of gadolinium. Areas of lower signal intensity inside of the lesion were suggested as incorporated cranial nerves. A left retro-sigmoidal approach in a semi-sitting position was chosen to expose the tumour. After reducing the tumour mass, the tumour was dissected from the cranial nerves which were incorporated into the tumour. The residual tumour was adherent to the brain stem and the encased lower cranial nerves, allowing only a near subtotal resection of the highly vascularized tumour in order to avoid neurological deficits. The histological examination revealed a lipoma. Attempts at complete removal of cerebellopontine angle lipomas usually result in severe neurological deficits. Conservative treatment should therefore be preferred. Limited surgery is indicated if the patients suffer from disabling neurological symptoms and signs e.g., vertigo, nausea, trigeminal neuralgia, facial weakness or facial spasm.