CD7-CELL LEUKEMIA-LYMPHOMA - FEATURES OF A SUBGROUP WITHOUT CIRCULATING BLAST CELLS( STEM)

Recent advances in immunology have clarified the cellular origin of he matopoietic neoplasms. Blast cells with a CD7+ CD4- CD8- phenotype are demonstrated to originate from malignant pluripotent hematopoietic st em cells. In this article, the authors describe three rare cases, desi gnated as a lymphoma type of CD7+ stem cell leukemia/lymphoma, with cl inical features described below. All three patients were admitted with non-Hodgkin lymphoma with a 2-month to 4-month history of lymphadenop athy. Histologic examination of lymph nodes showed lymphoblastic lymph oma (LBL) in all patients. Bone marrow blast cells had an immunophenot ype consistent with CD7+ CD4- CD8- acute leukemia, although abnormal c ells were not observed in the peripheral blood during the course of th e disease. One patient had a recurrence in the bone marrow, with myelo peroxidase-positive blast cells expressing myeloid differentiation ant igens. Chromosomal analysis detected a common abnormal karyotype initi ally and at relapse. Furthermore, the same T-cell receptor gene rearra ngement was found initially and at relapse, suggesting that these blas t cells originated from the same pluripotent leukemic clone. Additiona l studies on more patients are required to determine the clinical sign ificance of this group, including the difference from CD7+ stem cell l eukemia/lymphoma with circulating blast cells (leukemic type) or LBL.