Neurofibromatosis Type 2
Neurofibromatosis type 2 (NF2) is an autosomal-dominant genetic syndrome characterized by the development of vestibular schwannomas (VS), meningiomas, ependymomas, spinal schwannomas, gliomas and posterior subcapsular lenticular opacities. This disorder is caused by biallelic loss of the NF2 gene on the long arm of chromosome 22. NF2 codes for the tumor suppressor protein merlin (moesin, ezrin, and radixin-like protein). While 50 percent of individuals with NF2 have an affected parent with the disease, the remaining 50 percent have de novo gene mutations. Patients with germ-line mutations in NF2 develop bilateral VS; however, unilateral, sporadic tumors are far more common, making up 95 percent of VS. Whether the neoplasms are sporadic or due to NF2, NF2 gene mutations are present in nearly 100 percent of VS tumors.
Typically, symptoms start appearing in adolescence/early adulthood, including sensorineural hearing loss, tinnitus, dizziness/vertigo (feeling that the world is spinning when you are not moving), headaches, facial numbness and facial weakness or paralysis. People with NF2 can sometimes develop other symptoms due to gliomas, meningiomas and schwannomas along the spinal nerves. They may also experience progressive visual impairment due to cataracts.
As a Neurotologist, Dr. Jacob is involved in the diagnosis and management of vestibular schwannomas (acoustic neuromas) as well as posterior cranial fossa meningiomas in patients with NF2. Referral to neurosurgery for the management of other tumors, ophthalmology for visual concerns, pain management specialists for chronic pain and genetic counselors may also be indicated. Workup for VS includes a complete medical history, cranial nerve examination, comprehensive audiogram, videonystagmography (VNG) and vestibular evoked myogenic potentials (VEMP) to evaluate balance function, an MRI scan of the brain with internal auditory canal protocols to confirm the presence/size of each tumor and a temporal bone CT scan to delineate skull base anatomy.
Because VS are typically slow growing and benign, observation using serial MRI scans is an option if tumors are small and not causing any neurologic symptoms. For small tumors with preserved hearing, Dr. Jacob also provides patients/families with the option for hearing preservation surgery (middle cranial fossa or retrosigmoid approaches). If hearing cannot be preserved during the operation, Dr. Jacob makes every effort to save the cochlear nerve on the operated side as it provides patients with the option of cochlear implantation in the future. In close partnership with neurosurgery, he offers the full complement of surgical approaches, including the translabyrinthine approach, retrosigmoid approach, middle fossa approach and petrosal approach to his patients. The use of stereotactic radiation therapy in patients with NF2 is controversial. The goal of radiosurgery is to stop the growth of the tumor, but the tumor is not removed. Stereotactic radiation is most commonly performed in patients who are not good surgical candidates; however, any patient can elect this option.
Why Choose Us
- Dr. Abraham Jacob, Medical Director for Ear & Hearing (E&H) at the Center for Neurosciences (CNS), is fellowship trained in Otology, Neurotology, and Cranial Base Surgery. He is the first and most experienced Neurotologist recruited to Southern Arizona and uniquely qualified to direct the evaluation and management of NF2.
- Dr. Jacob was a founding member of the University of Arizona (UA) Department of Otolaryngology prior to his departure and transition to CNS. At UA, he was Vice Chair of ENT and held the rank of full Professor with Tenure. He was also founding Director of the UA Ear Institute.
- Dr. Jacob transitioned his practice to the Center for Neurosciences in early 2017 as he felt that the new environment helped him to optimize delivery of personalized ear and lateral skull base care.
- Dr. Jacob’s surgical expertise as a temporal bone, skull-base surgeon is supported by an extensive clinical infrastructure at both CNS and the Tucson Medical Center, bringing together tertiary care operating rooms, neurosurgery support, neuroradiology, and a neuro/critical care ICU.
- Dr. Jacob has published dozens of papers on temporal bone surgery, including surgery for acoustic neuromas. In partnership with Neurosurgery, he is able to perform translabyrinthine, middle fossa, and retrosigmoid approaches to these tumors. Dr. Jacob has presented cutting-edge research on the pathobiology of vestibular schwannomas at both national and international meetings. When involved in basic science research during his time at Ohio State and UA, he received over 1.5 million dollars of extramural grant funding to study the behavior and treatment of these tumors.