Pathomorphology of acute lymphoblastic leukaemia in childhood: convolution of lymphoblast nuclei.

In the period between 1960--1978 36 children dead with acute lymphoblastic leukaemia (ALL) were studied. Nine cases were found to be in pathological remission, i.e., without any leukaemia infiltrations (7 of these were seen in the last 5 years). The remaining 27 could be divided into two groups on the basis of nuclear structure: in 20 cases the lymphoblastic nuclei were round or oval and their convolution was pycnotic, "highly convoluted", or lobulated, in 7 the nuclei were round or oval and their convolution was slight. The survival was 10.8 months in the first and 3.6 months in the second group. Although the origin and the degree of differentiation of the cells of these two groups are not clearly known, it seems that the two types represent different stages of T-lymphoblast evolution.