Evolution of Vestibular Schwannoma After Removal of Epidermoid Cyst of the Same Location
A 71-year-old man presented with vestibular schwannoma manifesting as hearing disturbance and truncal ataxia 16 years after removal of a cerebellopontine angle (CPA) epidermoid cyst, and located adjacent to the remnant lesion. The patient first presented with a 6-month history of right trigeminal neuralgia. Neuroimaging demonstrated a right CPA lesion, suggestive of an epidermoid cyst. Right lateral suboccipital craniotomy was performed and the histological diagnosis was epidermoid cyst. A
... lesion remained, but the symptoms were relieved. Sixteen years later, the patient presented with right auditory disturbance, vertigo, and truncal ataxia. Magnetic resonance imaging revealed a multiple cystic mass adjacent to the remnant epidermoid cyst in the right CPA. The lesion was removed and the histological diagnosis was vestibular schwannoma associated with the epidermoid cyst. The irritative effect of the remnant epidermoid cyst or surgical procedures may have caused the vestibular schwannoma, but no evidence of the evolution of the different types of tumors was found.