[Occult nasopharyngeal carcinoma (author's transl)].

Clinical and histological examination of a cervical lymph node, removed from a 15-year-old boy, revealed nasopharyngeal carcinoma as the probable diagnosis. But the decisive diagnostic pointer was a markedly raised Epstein-Barr virus antibody titre, which gives the diagnosis at a time when there may not as yet be clinical evidence of carcinoma. Serial serum titre determinations are of prognostic value: with increasing spread of the tumour there is a rise in antibody titre. Autopsy confirmed that the nasopharynx had been the site of the primary tumour.