An olfactory neuroblastoma presenting as posterior reversible leukoencephalopathy syndrome.

Olfactory neuroblastomas are rare malignancies of the nasal and sinus cavities. They have been associated with paraneoplastic syndromes due to secretion of adrenocorticotropin hormone (ACTH) or antidiuretic hormone. These associated paraneoplastic syndromes can present with a wide variety of symptoms that can make diagnosis of the underlying tumor difficult. Here we present the case of a 23-year-old woman who had a seizure due to the development of posterior reversible leukoencephalopathy syndrome because of secondary hypertension due to Cushing's syndrome, which was in turn found to be due to ectopic ACTH production from a metastatic olfactory neuroblastoma.