Ectopic primary olfactory neuroblastoma of the nasopharynx: A case report and review of the literature.

Olfactory neuroblastoma (ONB, also called esthesioneuroblastoma) is a rare malignant tumor of neuroectodermal olfactory cells. We report a case of an undifferentiated ONB with unfavorable histology arising ectopically in the nasopharynx. The patient was a 15-year-old male who presented with a right-sided painful neck mass, nasal obstruction, and weight loss. Awareness of the ectopic ONBs, although exceedingly rare, is important when considering differential diagnoses of sinonasal tumors as treatment and prognosis may differ from other lesions.