CD7, CD34-POSITIVE STEM-CELL LEUKEMIA ARISING IN AGNOGENIC MYELOID METAPLASIA

Agnogenic myeloid metaplasia (AMM) is a chronic myeloproliferative dis order arising from a single hematopoietic cell. Approximately 5% of re ported cases of AMM have terminated in leukemic crisis; however, the p recise characteristics of the leukemic cells have rarely been reported . We report a case of AMM that occurred in a 42-year-old man and was c omplicated by leukemic transformation. The leukemic cells wer morpholo gically lymphoblastoid cells with a negative reaction to peroxidase st aining, and phenotypically characterized as CD7+, CD34+, HLA-DR+, CD4- , CD8-,CD10-, CD13-, and CD33-. Southern blot analysis revealed that T cell receptor-beta,gamma, and immunoglobulin heavy chain genes in leu kemic cells were retained in germ-line configuration. These observatio ns suggest that leukemic cells in our case involved early hematopoieti c stem cells rather than those strictly committed to myeloid or lympho id precursors. To our knowledge, this is the first report of stem cell leukemia arising in a patient with AMM. (C) 1993 Wiley-Liss, Inc.