Olfactory neuroblastoma invading the oral cavity in a patient with inappropriate antidiuretic hormone secretion.

Olfactory neuroblastoma is an uncommon intranasal neoplasm that has not been previously documented to invade the oral cavity. The tumor's variable clinical manifestations and microscopic features may create a diagnostic dilemma for the clinician. The neoplasm has been identified as a direct cause of ectopic arginine vasopressin production leading to inappropriate antidiuretic hormone secretion. An unusual case of olfactory neuroblastoma invading the oral cavity through the maxillary sinus in a patient with pathologic antidiuretic hormone secretion is reported.