核の自己崩壊像を呈する芽球を末梢血中に多数認めた小児L₃ ALLの1例

抄録

L3 ALL is quite a rare type of childhood leukemia accounting for less than 1% of ALL according to the reports. We have encountered a patient with L3 ALL whose blastic cells showed autokaryolysis in the peripheral blood during which severe DIC was observed. We have never found such a case in the literature, thus, the cell morphology and the clinical course are reported with a brief discussion.
A six-year-old boy was admitted because of fever and swelling of the mandibula. Bone marrow examination revealed many blastic cells with prominent and intensely basophilic cytoplasm, and prominent vacuoles. PAS reaction was positive, but that of peroxidase was negative. Surface marker analysis showed that cytoplasmic Ig was positive, but any of T cell markers were negative (Surface Ig could not be analyzed). Thus the diagnosis of L3 ALL was made, and a chemotherapy consisted of prednisolone and vincristine was started. However, the number of WBC tended to increase after the start of steroid therapy. 50% of the increased leukocytes were blastic cells and 25% of the cells were morphologically quite different from the typical blasts. These atypical cells showed prominent basophilic cytoplasm, which was nearly same as that of blastic cells, but the nuclei tended to break down (possibly autokaryoklasis). The cells had several small nuclei. After the initiation of the vincristine treatment, the leukocyte count rapidly decreased, and a marked bleeding tendency due to DIC occurred. Heparin therapy apparently resulted in an improvement of the bleeding tendency. The patient obtained a hematological complete remission three weeks following admission, however he relapsed soon.