Abstract
A case of acute myelogenous leukemia, 27-year-old woman with increased activity of terminal deoxynucleotidyl transferase (TdT) in blast cells, is reported. Hematological examinations on admission revealed that WBC count of peripheral blood was 26,600/mm3 with 88.5% myeloblasts, and nucleated cell count of bone marrow was 355,000/mm3 with 77.2% myeloblasts. The blasts had a myeloid appearance with Auer rods on light microscopy, and were positive for peroxidase, and negative for PAS. TdT activity was 15.8 U/109 cells, which was definitely high, compared with other 4 cases of AML (<0.1 U/109 cells). Chemotherapy including vincristine and prednisolone was given, but it was not effective, and she died 9 months after admission. The significance of TdT activity in various types of leukemia is discussed.
