What a Neurosurgeon Should Know About the Endolymphatic Sac: Part 2 - Diagnosis and Management of the Endolymphatic Sac Tumors

Objective This article is divided into three parts. In the second part of this review, the authors focus on describing the endolymphatic sac tumor and presenting illustrative cases.Methods A review of previous studies, from 1957 to 2021, from basic and translational research using human and animal endolymphatic sac (ES) tissue or cells, as well as other reviews on this theme.Results The ES is an inner ear structure, which is responsible for the homeostatic regulation, as well as endolymphatic fluid volume control, immune response etc. One of the possible alterations of the ES is the ELST, a low-grade malign neoplasm that originates from the epithelium of the endolymphatic duct and sac. The clinical presentation of the ELST includes hearing loss, tinnitus, headache, and vertigo. The diagnosis in the early stages is rare, given that this group of symptoms is very similar to other, more common, diseases such as the Meniere syndrome. Its diagnosis is made by computed tomography (CT), magnetic resonance imaging (MRI), immunohistochemistry, and confirmed by histopathology. However, none of these examinations are part of the pathological guidelines for ELST. The treatment for ELST in the early stages has a high rate of success.Conclusion The ELST is a very difficult diagnosis due to its presentation. Furthermore, the interactions between ELST and the Von Hippel-Lindau disease usually result in a more aggressive condition. Despite the difficulty of the diagnosis, doing it early increases the chances of successful treatment.