LAUSR

Oligodendrogliomas, the third most common primary gliomas, have a strict molecular definition, characterized by the combined presence of IDH mutation and 1p19q codeletion. Here in, we describe an extremely unusual case of molecularly-defined anaplastic oligodendroglioma with transdural extension into the frontal and ethmoid sinuses, without prior neurosurgical intervention or radiotherapy. The molecular profile of the tumour will also be provided. To the best of our knowledge, this has never been reported before. Most of the previously reported glial tumours with transdural extension were cases of histologically proven glioblastoma and gliosarcomas, typically seen in the context of prior neurosurgical intervention and/or radiotherapy. This case adds to the limited literature on oligodendrogliomas with transdural extension. Further studies are needed to elucidate the relationship between the incidence of transdural extension and the molecular subtypes of oligodendrogliomas.