Rare synchronous association of vestibular schwannoma and indolent insular oligodendroglioma in a patient without neurofibromatosis: controversial issue of timing for surgical treatment of asymptomatic low-grade gliomas

Maurizio Iacoangeli,¹ Alessandro Di Rienzo,¹ Roberto Colasanti,¹ Lorenzo Alvaro,¹ Niccolò Nocchi,¹ Gabriele Polonara,² Lucia Giovanna Maria Di Somma,¹ Antonio Zizzi,³ Marina Scarpelli,³ Massimo Scerrati<sup>1

1</sup>Department of Neurosurgery, ²Department of Radiology, Section of Neuroradiology, ³Department of Pathology, Università Politecnica delle Marche, Umberto I General Hospital, Ancona, Italy

Abstract: The co-occurrence of a vestibular schwannoma and a low-grade glioma is rare, and even rarer is the association with an oligodendroglioma. Although various authors have addressed the problem of treating patients with incidentally discovered indolent low-grade gliomas, an established protocol does not exist to date. The common approach is to reserve surgery until there is radiological evidence of tumor growth or high-grade transformation. However, because incidental low-grade glioma may represent the first stage of unavoidable pathological progression towards high-grade glioma, early and radical surgical resection should be advocated in order to increase the chance of a "cure" and prolonged survival. This case report supports this view, and suggests reflection on a possible change from a conservative philosophy to preventative surgical treatment.

Keywords: multiple primary intracranial tumors, vestibular schwannoma, oligodendroglioma, indolent low grade gliomas, incidentaloma, surgery