Olfactory neuroblastoma (esthesioneuroblastoma) and esthesioneuroepithelioma: histologic and immunohistochemical study.

Two cases of olfactory neuroblastoma (ONB) representing two morphological variants of the tumor are described. Case 1 exhibited a neuroblastoma-like histological pattern corresponding to the usually reported type of ONB--the esthesioneuroblastoma, whereas in case 2 a very rare variant of ONB-the esthesioneuroepithelioma was recognized. The histological and immunohistochemical differences between the cases are discussed with regard to still controversial opinions concerning the subclassification of ONB and the histogenesis and clinical prognosis of these tumors.