A 35-year-old woman presents with a two-month history of worsening headaches, dizziness, and right-sided tinnitus. MRI reveals a well-circumscribed, enhancing lesion at the right cerebellopontine angle (CPA). The mass is causing compression of the adjacent cerebellum and brainstem, and it extends into the internal auditory canal. There is no associated hydrocephalus or hemorrhage. A smaller but similar lesion is seen on the left which led to a subsequent diagnosis of neurofibromatosis type 2, a condition which is associated with which of the following lesions?