Genetic analyses permit the differentiation between reactive malfunctions ('promyelocyte arrest') and arising promyelocyte leukemia in a pregnant patient with a history of a medulloblastoma.

We report the case of a 24-year-old woman with a history of radiotherapy for a cerebellar medulloblastoma 2 years prior to detection of a lymph node metastasis of the former disease and a pancytopenia in the peripheral blood. On bone marrow (BM) examination promyelocyte leukemia vs. a reactive 'promyelocyte arrest' were discussed. The translocation t(15;17) was found in some nuclei and there was a PML-RARalpha gene rearrangement detectable by RT-PCR. Furthermore, there was BM infiltration by the primary cancer. All these results led to the diagnosis of a relapse of the medulloblastoma and of a beginning promyelocyte leukemia. As the patient was pregnant, she had to be parted with the baby to facilitate intensive chemotherapy. She did not respond to a therapeutic regimen specific for promyelocytic leukemia but achieved complete remission of the medulloblastoma as well as the leukemia after the administration of polychemotherapy specific for medulloblastoma. One year later, she suffered from a relapse of her leukemia. Now nearly all cells showed a t(15;17) aberration. Immunophenotype analyses showed a shift to a more undifferentiated blast phenotype that was, however, still HLA-DR negative. The patient again received chemotherapy for leukemia but developed a sepsis 3 months later and died of pancytopenia ensuing her leukemia. There was no clinical evidence for recurrence of the medulloblastoma.