Computed tomographic findings of a nasal neuroendocrine neoplasm with intracranial extension in a horse

A 20-year-old Irish Sport Horse gelding was presented to the Royal Veterinary College Equine Referral Hospital for investigation of left-sided epistaxis, depression and gait abnormalities of approximately 1 month duration. Physical examination and cranial nerve evaluation were unremarkable. A small amount of haemorrhagic discharge was noted from the left nostril. Gait evaluation was suggestive of proprioceptive deficits. Computed tomography (CT) identified a mass lesion within the left conchofrontal and sphenopalatine sinuses extending through the cribriform plate into the calvarium. Histopathology of the mass revealed a neuroendocrine neoplasm, for which a diagnosis of esthesioneuroblastoma was favoured. This case highlights the usefulness of CT for the identification and extent of an intracranial mass and therefore its prognosis, however, histopathological examination was necessary to confirm the diagnosis.