Immunophenotypic analysis of extranodal non-Hodgkin's lymphomas in the oral cavity.

Fifty cases of extranodal non-Hodgkin's lymphoma arising in the oral cavity were reclassified using the updated Kiel classification. In order to determine the antigenic phenotype of the proliferating cells in oral lymphoma, we used a panel of paraffin effective antibodies that are known to react with lymphocyte- and histiocyte-associated antigens. The median age of the patients was 53 years, with a male predominance (M:F = 1.9: 1). The great majority of oral non-Hodgkin's lymphomas were B-cell lymphomas. There were 12 low-grade B-cell lymphomas (comprising one mucosa-associated lymphoid tissue, four centrocytic and seven centroblastic-centrocytic lymphomas) and 25 high-grade tumors (comprising 17 centroblastic, two immunoblastic, two Burkitt's and four lymphoblastic lymphomas). All 37 B-cell malignancies showed reactivity for L 26 and KiB 3. A monotypic immunoglobulin staining pattern, as revealed by light chain restriction, was found in 21 cases (57%) of the non-Hodgkin's lymphomas confirming their B-cell origin. Furthermore, monotypic staining for kappa-chain predominated (16/21 kappa, 5/21 lambda). Only a small number (6 cases) was of T-cell lineage and all cases showed positive reaction for UCHL 1, MT 1 and DFT 1. In one of six T-cell lymphomas, Ber-H 2 positive anaplastic large cell lymphoma was detected. Such a case was documented for the first time in the primary extranodal non-Hodgkin's lymphoma of the oral cavity. Five cases could be assigned with certainty to the histiocytic system. These cases were positive for cathepsin D and KP 1 LN 3, which recognized Ia (HLA-DR) antigens, was demonstrated most frequently in high-grade B-cell lymphomas, T-cell lymphomas and true histiocytic lymphomas.