Epstein-Barr virus detection by in situ hybridization in fine-needle aspiration biopsies

Metastasis to neck lymph nodes is often the presenting symptom of occult head and neck tumors, including undifferentiated nasopharyngeal carcinoma (UNPC). The diagnosis of the primary site of the tumor by conventional cytological analysis of tissue obtained by fine-needle aspiration (FNA) may be difficult. As Epstein-Barr virus (EBV) infection is consistently associated with UNPC, we evaluated the diagnostic significance of EBV detection using a nonradioisotopic in situ hybridization assay. The data obtained by FNA from metastatic head and neck tumors was correlated with the histology of the corresponding surgical specimens. In a series of 25 FNA specimens of cervical lymph node metastases of tumors of unknown origin, EBV was found expressed in all seven metastases of UNPC but in none of 18 metastases of tumors of different types. Therefore, detection of EBV in cervical metastatic adenopathy may be successfully used to identify the presence of occult UNPC.