Ki-1+ cutaneous lymphoma. Gene rearrangement analysis of tumor cells in tissue and short-term culture of a patient.

Cutaneous malignant lymphomas developed in an 80-year-old man without any evidence of leukemic disseminations of lymphoma cells. Immunohistologic staining showed the expression of Leu-3a, Leu-4, Ki-1, Tac, and HLA-DR antigens on tumor cells in tissue and large lymphoid cells in long-term, interleukin 2-containing culture of tumor explants. DNA samples extracted from the skin tumors and cultured lymphoid cells showed a clonal rearrangement of T-cell receptor (TCR) gene C beta 1 with the molecular size of 9 kilobases. These findings suggested the T-cell origin of Ki-1+ cutaneous lymphoma cells and the occurrence of a clonal proliferation of tumor cells in culture.