ABSTRACT
OBJECTIVE: The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been reported as a paraneoplastic syndrome in many different types of malignancies. Several case reports of SIADH have been reported in patients with olfactory neuroblastoma (ONB), but the exact incidence is unknown. The purpose of this study was to review our experience with olfactory neuroblastoma and to identify all patients who had a history of SIADH prior to the diagnosis of ONB. STUDY DESIGN: Case series and chart review. SETTING: Tertiary care university-affiliated medical center. SUBJECTS AND METHODS: A total of 21 patients presented to our institution with ONB between 1997 and 2009. All records were reviewed for a history of preoperative hyponatremia or SIADH. RESULTS: Three patients were identified who had a history of SIADH prior to the diagnosis of ONB. Immunohistochemical staining of the tumor specimens from the 3 patients with SIADH was positive for arginine vasopressin. SIADH resolved in all 3 patients after successful treatment of ONB. CONCLUSION: Although uncommon, SIADH can be the presenting symptom of ONB and should be considered during the workup for idiopathic SIADH.
