An Uncommon Case of Pediatric Esthesioneuroblastoma Presenting as SIADH: 18F-FDG PET/CT in Staging and Post-Therapeutic Assessment.

Esthesioneuroblastoma (ENB) is an uncommon neuroendocrine tumor originating from the olfactory neuroepithelium and accounts for 3-6% of all intranasal tumors [¹]. ENBs can be locally aggressive and cause invasion and destruction of surrounding structures. Histological grading and clinical stage at presentation are highly predictive of survival and especially presence of lymph node and distant metastases are determining prognostic factors [²,³,⁴,⁵]. Thus, reliable imaging is essential in these patients. Conventional imaging modalities for staging ENB are magnetic resonance imaging (MRI) and computed tomography (CT). However, fluorine-18 fluoro-2-deoxy-d-glucose positron emission tomography/CT (18F-FDG PET/CT) has been reported as a valuable adjunct and was found to upstage 36% of ENB patients compared to conventional imaging [6]. We present a case demonstrating the diagnostic work-up and follow-up with 18F-FDG PET/CT in a young patient with ENB with a highly atypical clinical presentation.