Lipomatosis of the Trigeminal Nerve Causing Trigeminal Neuralgia: Case Report and Literature Review

ABSTRACT Cerebellopontine angle lipomas are rare and attempts at surgical excision are associated with significant morbidity. Lipomatosis of nerve, the fatty infiltration of nerves, is a distinct entity. We present a case of intractible trigeminal neuralgia caused by lipomatosis of the trigeminal nerve. Clinical case: A 25-year-old male presented with severe right-sided trigeminal neuralgia. Imaging showed a lesion involving the trigeminal nerve with signal characteristics of fat. At surgery the lesion was found to be a fatty infiltration of the nerve itself. Surgery was therefore limited to arachnoid adhesiolysis. The patient remains symptom-free and neurologically intact to date. Correctly identifying these lesions as lipomatosis of nerve rather than lipoma of the cerebellopontine angle make it clear that even partial surgical excision will inevitably result in neurological deficit and should not be attempted. However, in the case of intractable trigeminal neuralgia we demonstrate that surgery can still play a role.