EBV genome and immunoglobulin gene rearrangement in the differential diagnosis of nasopharyngeal carcinoma and lymphoma.

Head and neck tumors include nasopharyngeal carcinoma (NPC) and lymphoma. The differential diagnosis of these tumors is based on histology, immunocytochemical staining, and EBV serology. In rare cases it might be difficult to distinguish between NPC and lymphoma in HE section or biopsies. DNA hybridization with cloned EBV and human immunoglobulin gene fragments allows the detection of EBV-related sequences and immunoglobulin gene rearrangements. The presence of EBV genome supports the diagnosis of NPC or EBV related BL, while rearrangement of immunoglobulin genes points to B-cell lymphoma. The diagnosis in 11 patients suspected of head and neck tumors was carried out by hybridization of DNA extracted from the tumors and assayed with cloned EBV and IgHCJ DNA probes. One patient proved to have EBV-associated BL based on positive hybridization with EBV probes and immunoglobulin rearrangement, presenting a unique hybridization with cloned EBV DNA BamHI W fragment, with bands of 3.2 and 3.9 kb. BL was confirmed in this patient by demonstration of c-myc rearrangement. A second patient was negative in hybridization with EBV, and positive for immunoglobulin rearrangement, and therefore was diagnosed as having B-cell lymphoma. In seven patients NPC was confirmed by hybridization with EBV-DNA probes. In two patients, both NPC and B-cell lymphomas were excluded.