Epstein-Barr virus detection in neck metastases by in-situ hybridization in fine-needle aspiration cytologic studies: An aid for differentiating the primary site

Background. Nasopharyngeal carcinoma (NPC) is strongly associated with Epstein-Barr virus (EBV). The metastasis to cervical lymph nodes represents a frequent initial manifestation of NPC. The usefulness of EBV detection by polymerase chain reaction (PCR) in the diagnosis of occult NPC with cervical metastasis has been reported. Our previous study showed that EBER1 in-situ hybridization was somewhat more sensitive and specific than PCR in detecting EBV in the evaluation of specimens from a population at high risk for NPC. Methods. Fine-needle aspiration cytologic specimens of neck masses from 30 patients were investigated, including 10 NPC primary tumors, 19 squamous cell carcinomas from other sites of the head and neck (9 oral cavity, 2 paranasal sinuses, 2 oropharynx, 3 larynx, and 3 hypopharynx), and 1 diffuse large-cell lymphoma. EBER1 in-situ hybridization was performed on direct smears made from aspirates. Results. EBER1 signals were detected in all neck metastases from the nasopharynx but none of the specimens from other primary sites. Conclusions. This study suggests that EBER1 in-situ hybridization can be used as a supplement tool for differential diagnosis whenever fine-needle aspiration cytologic examination is presented with a neck metastasis without the primary site. (C) 2000 John Wiley and Sons, Inc.