Transient leukemoid disorder in a newborn with Down syndrome followed 19 months later by an acute myeloid leukemia: demonstration of the same structural change in both instances with clonal evolution.

A transient leukemoid disorder (TLD) was observed in a newborn with Down syndrome (DS), demonstrating a clonal abnormality: 47,XX,der(X;15)(p10;q10),+21(c). Spontaneous remission was observed, but 19 months later an acute leukemia from the myeloid series was discovered. Cytogenetic study revealed the same structural change as at birth, with karyotypic evolution corresponding to addition of one chromosome 8 and a fourth chromosome 21. These findings demonstrate, at least in our patient, that TLD and the subsequent acute leukemia are closely related and that TLD, closely related to DS, must be viewed as a preleukemic disorder undergoing spontaneous remission. A review of literature data shows that most cytogenetic studies reported so far are related to either TLD or acute leukemia in DS. Serial studies performed in the same patient are quite infrequent and, to the best of our knowledge, there is only one other report demonstrating a cytogenetic relation between TLD and the subsequent acute leukemia.