Epstein-Barr virus detection in neck metastases by polymerase chain reaction.

Cervical nodal metastasis from occult carcinomas represents a diagnostic challenge. This is a common presentation of undifferentiated nasopharyngeal carcinoma (UNPC), but metastatic carcinomas from other sites must be considered. UNPC has the distinguishing feature of a close association with Epstein-Barr virus (EBV). Since the polymerase chain reaction (PCR) can detect EBV in archival tissues, it offers significant advantages over previous methods for the detection of viral genomes. Its extreme sensitivity allows analysis of small samples from needle aspirates. Using the polymerase chain reaction to amplify EBV sequences from archival tissues, 15 of 18 NPC samples were positive for EBV. Of these 18, 14 of 14 with UNPC were positive, 1 of 2 with squamous cell carcinoma (SCC) were positive, and 10 of 2 with adenocarcinoma were positive. All 6 UNPC metastatic to lymph nodes were positive. Carcinoma metastatic to cervical nodes from 17 of 17 non-UNPC occult primaries lacked EBV. This demonstrates the utility of EBV detection by the polymerase chain reaction in the evaluation of patients with metastases to neck nodes from occult primary carcinomas in order to identify cases of UNPC.