Esthesioneuroblastoma. Intermediate filaments, neuroendocrine, and tissue-specific antigens.

Esthesioneuroblastoma (EN), a malignant neuroblastic tumor arising in the superior portion of the nasal cavity, shares histologic similarities with a number of primary malignant tumors that arise in this region, including rhabdomyosarcoma, lymphoepithelioma, and lymphoma. To establish an antigenic profile of EN as an aid in the differential diagnosis of these histologically similar nasal tumors, immunostaining was performed for the following intermediate filaments: keratin, neurofilament, glial fibrillary acidic protein, and desmin; neuron-specific enolase (NSE), S-100 protein, chromogranin, human common leukocyte antigen (HLE), epithelial membrane antigen (EMA), myoglobin, and carcinoembryonic antigen (CEA) on 21 primary nasal tumors: eight EN, five lymphoepitheliomas, two small cell carcinomas, three lymphomas, and three rhabdomyosarcomas. Keratin and CEA stained only the carcinomas (6/7+, 4/7+), respectively; desmin and myoglobin only rhabdomyosarcoma (3/3+, 1/3+); and HLE only lymphomas (3/3+). Chromogranin and neurofilament staining occurred exclusively in one case each of EN. S-100 and NSE commonly stained EN (5/8+, 6/8+), but carcinomas (1/7+, 2/7+) and rhabdomyosarcomas (1/3+, 3/3+) were also positive. Despite the apparent nonspecificity of NSE and S-100, an antigenic profile of positive NSE of S-100 staining with negative epithelial, muscle, and lymphoid antigens uniquely identified six of eight EN. Chromogranin and neurofilament positivity was further evidence for EN in two cases. This antigenic profile is a helpful adjunct in the diagnosis of EN and other primary malignant nasal tumors.