J Neurol Surg B Skull Base 2016; 77 - P121
DOI: 10.1055/s-0036-1580066

Vestibular Schwannoma and Pituitary Adenoma in the Same Patient: Coincidence or Novel Clinical Association?

Neil S. Patel 1, Jeffrey T. Jacob 2, Michael J. Link 3, Colin L.W. Driscoll 1, Matthew L. Carlson 1
  • 1Department of Otorhinolaryngology, Mayo Clinic, Rochester, Minnesota, United States
  • 2Michigan Head and Spine Institute, Southfield, Michigan, United States
  • 3Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

Objective: Our group has cared for several patients with coexistent vestibular schwannoma (VS) and pituitary adenoma (PitA). While there is no presently known syndromic relationship between these two entities, the observed incidence raises the question of whether a common etiopathogenesis exists in this subset of patients. Herein we describe this group of patients to better characterize this association.

Materials and Methods: A retrospective review of records from 2000 through 2014 was performed at a single tertiary care academic referral center. Adult patients with a new diagnosis of PitA and VS were included.

Results: Ten patients were included. Of these, 6 were men. The median patient age at VS and PitA diagnosis was 58 years (range 36–66 years) for each. Median VS size at diagnosis was 9.4 mm (range 3–22 mm) in greatest dimension. Median radiologic follow up was 38 months (range 0 to 111 months). Four patients underwent stereotactic radiosurgery for treatment of their VS, 1 underwent microsurgical resection, and 4 tumors were observed with serial MRI. The four untreated tumors did not show radiologic evidence of growth over a median 37-month follow up period. Four patients had pituitary macroadenomas, defined by a minimum size of 10 mm. One PitA was a functioning prolactinoma, while the rest were nonfunctioning benign adenomas. Four patients were treated for PitA by transsphenoidal resection, medical therapy, and/or radiation. At our institution, ~150 patients with a new diagnosis of VS are evaluated annually. Based on the estimated population-based incidence of PitA (3 per 100,000 person-years), the expected rate of coprevalent PitA and VS would be 1 in every 33,333 VS patients. The observed incidence of coprevalent PitA and VS during the study period was 1 in every 210 VS patients. Thus, the observed rate was 159 times greater than would be expected by random chance.

Conclusion: The observed number of patients diagnosed with both VS and PitA at our institution is markedly higher than would be expected by chance alone. This study supports the notion that a common genetic mutation or environmental trigger may be responsible for the development of these benign intracranial tumors. Future studies incorporating genetic testing may help further clarify this association.