Different clinical presentation of intralabyrinthine schwannomas - a systematic review / Diferentes apresentações clínicas do schwannoma intralabiríntico --- uma revisão sistemática

Abstract Introduction: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. Objective: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. Methods: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. Results: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. Conclusion: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.

Resumo Introdução: Schwannoma intralabiríntico é um tumor benigno, raro, que afeta as porções mais terminais dos nervos vestibular e coclear. Este tumor pode ser classificado, de acordo com sua localização na orelha interna, em 10 subtipos. Objetivo: Realizar uma revisão abrangente das manifestações auditivas mais frequentes secundárias ao schwannoma intralabiríntico e descrever os possíveis mecanismos fisiopatológicos subjacentes. Método: Revisão sistemática da literatura até outubro de 2017 nas bases de dados PubMed, Web of Science e Scopus. O critério de inclusão foi manifestações clínicas do schwannoma intralabiríntico. Três pesquisadores avaliaram de forma independente os artigos e extraíram informações relevantes. Exemplificamos com a descrição de um caso de schwannoma intralabiríntico subtipo intravestibular com múltiplas formas de apresentações clínicas. Resultados: Vinte sete estudos contemplaram nossos critérios de inclusão. O subtipo do schwannoma intralabiríntico mais comum encontrado foi o intracoclear, seguido pelo intravestibular. Todos os casos apresentaram alteração auditiva, normalmente perda auditiva progressiva. Conclusão: O diagnóstico de schwannomas intralabirínticos baseia-se em exames de ressonância magnética de alta resolução e deve ser incluído no diagnóstico diferencial de pacientes com queixas vestibulococleares. Apesar de termos aproximadamente 600 casos na literatura, ainda nos falta descrição detalhada da evolução clínica dos pacientes em correlação com achados na ressonância magnética de ossos temporais e o subtipo tumoral.

Different clinical presentation of intralabyrinthine schwannomas - a systematic review.

INTRODUCTION: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. OBJECTIVE: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. METHODS: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. RESULTS: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. CONCLUSION: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.