To describe the incidence of intralabyrinthine schwannoma (ILS) utilizing the Rochester Epidemiology Project (REP), a unique medical consortium in the United States that covers a complete population of all ages in a well-defined geographic area over the past half-century.
All patients with ILS diagnosed between January 1, 1966 and December 31, 2016 in Olmsted County, Minnesota, identified using the REP medical records-linkage system.
Incidence of ILS.
Fourteen incident cases of ILS were identified in Olmsted County since 1966—a period spanning 5.9 million person-years. Over the past decade, the incidence rate of ILS was 0.81 per 100,000 person-years and 1.1 over the last 5 years. Since 1966, the cumulative incidence rate of ILS over the past 50 years was 0.26 per 100,000 person-years. The median age at diagnosis was 60 years (interquartile ranges, 39–70). Incidence increased with age: over the last 5 years, those aged 60 to 69 exhibited an incidence rate of 2.7 per 100,000 person-years and those 70+ displayed a rate of 4.1. All patients had varying levels of asymmetrical sensorineural hearing loss with 64% of patients presenting with class D hearing. Four (29%) patients had a history of sudden sensorineural hearing loss, five (36%) reported imbalance and/or vertigo, and four (29%) reported aural fullness. Three of the 14 (21%) patients had neurofibromatosis type 2.
The incidence of ILS exceeds 1 per 100,000 person-years with modern diagnostic imaging. The rising incidence of ILS in recent years most likely reflects improved capacity for disease detection rather than a true increase in tumor development. Given the reputability of the REP consortium, these data suggest that ILS comprises a more common entity than previously considered.
*Mayo Clinic School of Medicine
†Department of Health Sciences Research
‡Department of Otolaryngology—Head and Neck Surgery
§Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
Address correspondence and reprint requests to Matthew L. Carlson, M.D., Department of Otolaryngology—Head and Neck Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; E-mail: Carlson.email@example.com
The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The currently submitted manuscript represents original research that has not been previously submitted and is not under consideration for publication elsewhere.
This study was made possible using the resources of the Rochester Epidemiology Project, which is supported by the National Institute on Aging of the National Institutes of Health under Award Number R01AG034676.
The associated abstract was submitted for poster presentation at the 2018 AAO-HNS meeting. We performed this research with approval from the Mayo Clinic and Olmsted County Medical Center Institutional Review Boards (IRB 15-006036 and 050-OMC-15, respectively).
The authors disclose no conflicts of interest.