Metastatic olfactory neuroblastoma invading a radiation-induced meningioma.

Olfactory neuroblastomas are malignant, neuroectodermal nasal tumours. We describe a 62-year-old patient with a recurrent olfactory neuroblastoma invading a radiation-induced meningioma. Given the temporal and spatial relationship between the primary lesion and the described recurrence, this was due to metastatic rather than direct contiguous spread, fulfilling all the criteria for true tumour-to-tumour metastasis. To our knowledge, this is the first description of an olfactory neuroblastoma metastasising to a meningioma.