[Connatal leukaemia and pseudoleukaemia--two cases with cytochemical findings (author's transl)]

Two newborn infants with hyperleukocytosis and blast cells in the peripheral blood are compared. Case 1 represents a connatal leukemia, which could be characterized as monocytic by the naphthol-ASesterase reaction, which was inhibited by NaF. The child died after a few hours. Case 2 must be diagnosed as "pseudoleukemia" in mongolism. The blast cells were classified as lymphoblastic on the basis of a strong granular beta-glucuronidase reaction. The patient achieved spontaneous remission.