ABSTRACT
Esthesioneuroblastoma is an uncommon tumour, and isolated primary involvement of the maxillary sinus is exceedingly rare. Esthesioneuroblastoma has infrequently been reported as a source of paraneoplastic ectopic hormone production. We report a case of isolated primary maxillary esthesioneuroblastoma, presenting as idiopathic syndrome of inappropriate antidiuretic hormone (SIADH). A 17-year-old girl presented with symptoms consistent with SIADH and no sino-nasal symptoms. MRI to exclude pituitary tumour revealed an isolated lesion of the right maxillary sinus. Biopsy demonstrated esthesioneuroblastoma. The lesion was removed endoscopically as a single en bloc specimen. Following resection, the sodium level returned to normal. This is only the third report in the literature of a primary maxillary esthesioneuroblastoma presenting as SIADH.
