[Immunohistochemical identification of olfactory esthesioneuromas. Apropos of 16 cases].

We report anatomoclinical and immunohistochemical analysis of sixteen cases of esthesioneuroblastomas. Microscopic study confirm difficulty of diagnostic for this tumors. Results of S 100 protein reaction for Schwann cells identification, NSE and HNK1 reaction for nervous cells and KL1 reaction for epithelial cells drawn from olfactory mucosa, allow definition of immunologic ENO profile. Pattern immunologic criteria are defined by S 100, NSE or/and HNK1, and eventually KL1 positive reactions permit differential diagnosis with other nervous tumors or undifferentiated carcinomas of nasal fossa. Histo-prognostic patterns are defined by S 100 reactivity distributed in neoplastic cells and cytoplasmic process of cells, to form a continuous network in well differentiated ENO and discontinuous network in undifferentiated forms of ENBO. These results confirm histogenesis of this tumor derived from olfactory mucosa and emphasized only two distinct types: neuro epithelial tumors corresponding to ENEO and cases of ENBO and nervous tumors grouping ENCO and any cases of ENBO.