Pathology and tumor microenvironment of vestibular schwannoma.

Vestibular schwannomas (VS) are WHO Grade 1 tumors arising from the vestibule-cochlear nerve and account for 8% of all intracranial neoplasms. In recent years, there has been a dramatic evolution in how the pathology of these tumors is regarded, and there is emerging interest in the role of the tumor microenvironment. In this chapter, we provide a comprehensive description of the pathology and microenvironment of VS, with a particular focus on the interlinked processes of immune cell infiltration and angiogenesis. Improved understanding of the pathophysiology of these tumors has already yielded therapeutic benefits in the form of bevacizumab for NF2-schwannomatosis-associated VS, and the potential role that immunomodulatory agents may play in the management of these patients will become clearer as our appreciation of the tumor microenvironment improves. Given the morbidity associated with current treatment options for VS, it is incumbent upon researchers to advance our understanding of this area so that we may use this information to develop new therapies and improve the care of our patients.