[Esthesioneuroblastoma: diagnostic conformation by immunohistology and electron microscopy]

The aesthesioneuroblastoma (olfactory neuroma) is a rare neuroepithelial tumour of the nasal cavity, the clinical symptoms of which become manifest very late in most patients. In general, with the light microscope used routinely (fixation of the specimens with formaldehyde, staining with haematoxylin-eosine) a malignant round cell neoplasia can be recognised without further differentiation. To ensure the diagnosis of an aesthesioneuroblastoma, immunohistological techniques (vimentin, S-100 protein, neurofilaments, neuron-specific enolase) are undoubtedly necessary. In some cases of unclear findings the electron microscope might be used to prove an aesthesioneuroblastoma. The immunohistological and electron microscopic features of aesthesioneuroblastoma are demonstrated and problems of histological differential diagnosis are discussed.