A 48-year-old woman from Mumbai is referred to neurosurgery with a 2-year history of progressive right-sided facial pain, initially in the V2 distribution, now spreading to V1 and V3. She also reports gradual onset of numbness over the right cheek and upper lip over the past 6 months. MRI brain with contrast shows a mass at the cerebellopontine angle compressing the trigeminal nerve root entry zone. What is the most likely diagnosis?