Role of immunohistochemistry in diagnosis of nasopharyngeal tumours.

To evaluate the usefulness of immunocytochemistry in the differential diagnosis of nasopharyngeal tumours, 35 undifferentiated nasal carcinomas were examined with a panel of monoclonal antibodies against a wide variety of epithelial and non-epithelial antigens. The results were compared with those obtained from a series of nasopharyngeal tumours comprising three squamous cell carcinomas, six lymphomas, one rhabdomyosarcoma, and one yolk sac tumour. All of the carcinomas were positive with at least one of the antiepithelial markers and negative for the leucocyte common antigen and were clearly distinguishable from the nasopharyngeal lymphomas, which gave the opposite staining pattern. It was concluded that such a panel of monoclonal antibodies would be extremely useful for the differential diagnosis of nasopharyngeal tumours, particularly with small or technically inadequate biopsies.