Abstract BACKGROUND Schwannomas are benign nerve sheath tumours, accounting for about 8% of intracranial tumours, with different histologic patterns described. Olfactory nerves are not expected to have Schwann cells, several theories exist about the origin of these tumours. METHODS/RESULTS A 16-year-old boy was admitted to the emergency department due to a first, self-limited, isolated epileptic event. He scored 15 in the GCS and no focal neurological deficits were observed. At that time, he complained about headaches, lasting for 3 months. Brain CT showed a frontobasal heterogeneous mass. MR characterized it as a 43X34X38 mm well-circumscribed mass, with solid and cystic areas, having an intimate relationship with lamina cribosa, with extensive vasogenic oedema surrounding it, causing deviation of adjacent structures. At that time, he was COVID-19 positive. He was submitted to a craniotomy with a transcortical approach, with an apparent total resection. Retrospectively, he became aware of an improved sense of smell after intervention. The histopathological study revealed a tumour composed of sheets and lobules of large, round cells showing immunopositivity for SOX-10 and S100 and with a Ki-67 index of 5-6%. We proceed to a molecular diagnosis, as the morphology was elusive, finding a methylation pattern highly close to those of schwannomas. With this presumptive diagnosis, clinical and radiological follow-up has been done. After two years, he is doing well, without signs of recurrence. CONCLUSIONS Although rare, an olfactory nerve schwannoma should be considered when there is a frontobasal tumour and impaired sense of smell, although in this case, the COVID-19 infection could be responsible for hyposmia. The clinical picture, imaging and histopathology description were not enough to make the diagnosis and, therefore, to plan the post-surgical approach. We emphasize the importance of a comprehensive molecular study, with a methylation classifier, as this tumour exhibits a typical DNA methylation pattern.