Describe two different neurological presentations that occurred as a result of rare cerebellopontine Epidermoid cysts.

Cerebellopontine Epidermoid cysts (EC) are extremely rare, accounting for less than 1% of all intracranial tumors and 5-7% of tumors located in the cerebellopontine region. They typically present with headache or CN VII-VIII palsies, though can less commonly present as Trigeminal neuralgia or temporal lobe epilepsy as seen in very few case reports. Diagnosis is made with MRI (T1 hypo-intense and T2 hyper-intense) and treatment relies exclusively on surgical resection, as they are not responsive to radiation or chemotherapy.

Case series and literature review.

Case (1): A 64-year-old man presented with a 24-year history of right Trigeminal neuralgia. He had initially responded to Carbamazepine, but symptoms continued to progress. MRI brain showed a 3.2cm EC over the right pontomedullary junction with involvement of the right Trigeminal nerve root entry zone leading to nerve atrophy. Patient plans to undergo surgical EC resection for treatment of compressive Trigeminal neuralgia.

Case (2): A 72-year-old woman presented with drug-resistant focal left temporal epilepsy. MRI brain showed a midline posterior fossa EC with extension into the bilateral mesial temporal lobes, left greater than right. Patient underwent partial EC resection along with left anterior temporal lobectomy and is now seizure-free.

ECs are rare congenital lesions that can cause neurologic symptoms from mass effect. According to the current literature, neurological symptoms are typically reversible with early surgical intervention. Because surgical intervention was delayed in both of our patients, there had already been atrophy and tumor invasion of affected structures; the first patient’s prognosis is unclear given presence of CN V atrophy, and the second patient required resection of mesial temporal lobe structures in addition to the EC for treatment of epilepsy. Thus, early treatment is essential in patients with these tumors.