Immunologic type of thyroid lymphoma in an adult T-cell leukemia endemic area in Japan.

Our previous study showed that thyroid non-Hodgkin's lymphoma (TL) in an adult T-cell leukemia/lymphoma (ATL) non-endemic area were exclusively B-cell derived. The present study was carried out to examine whether TL in an ATL endemic area are also exclusively of B-cell type. Eight cases with TL admitted to the hospital situated in an ATL endemic area were studied: they were all female with an age range from 50 to 75 (median 67) years. Histologically four of the eight cases showed a follicular pattern. Immunophenotypic study revealed all but one case to be of B-cell nature: CD3-, 4-, 8-, 20+, 22+, 45RA+, 45RO-, L22-, L24+/-, L28+. Neoplastic cells in one case with the histology of diffuse large cell lymphoma showed a CD3+, 4+, 8-, 20-, 22-, 45RA-, 45RO+/-, L22-, L24-, L28-, indicating a helper T-cell phenotype. Genotypic study showed rearrangement of T-cell beta-chain receptor in this case. This case also had antibodies against HTLV-1 in the serum. This case shows that it is also possible to develop T-cell TL in an endemic ATL area.