Extreme hyperleukocytosis in a pediatric T-ALL patient with a rare translocation, t(7;19)(q35;p13), and submicroscopic deletions at 4q25, 7q33 and 10q23

Although childhood T-cell acute lymphoblastic leukemia (T-ALL) is a high-risk disease the outcome can vary considerably. The varying outcomes suggest that unrecognized factors may contribute to disease progression. We report on a 2-year-old T-ALL patient presenting with a very short history of constipation and extreme hyperleukocytosis (WBC 882×109/L). In her leukemic cells we detected the very rare translocation t(7;19)(q35;p13) and LYL1 overexpression. Additionally, we detected submicroscopic deletions at 4q25, 7q33 and 10q23 by oligo-aCGH analysis. We suggest that LYL1 overexpression contributed to the leukemic state and propose that the observed microdeletions may have influenced to the rapid disease progression.