Systemic mastocytosis with associated myeloproliferative disease and precursor B lymphoblastic leukaemia with t(13;13)(q12;q22) involving FLT3.

摘要

Systemic mastocytoses represent neoplastic proliferationsof mast cells. In about 20% of cases systemicmastocytoses are accompanied by clonal haematopoieticnon-mast cell-lineage disorders, most commonly myeloidneoplasms. A case of systemic mastocytosis carrying thecharacteristic mutation at codon 816 (D816V) in the KITgene of mast cells, with two concurrent accompanyingclonal haematopoietic non-mast cell-lineage disorders,chronic myeloproliferative disease, unclassifiable andprecursor B lymphoblastic leukaemia is documented. Bothaccompanying clonal haematopoietic non-mast cell-lineagedisorders carried the wild-type KIT gene, but had anovel t(13;13)(q12;q22) involving the FLT3 locus at13q12. The chronic myeloproliferative disease, unclassifiableand the precursor B lymphoblastic leukaemia werecured by syngenous stem cell transplantation, but thesystemic mastocytosis persisted for more than 10 years.The additional impact of molecular techniques on thecorrect diagnosis in haematological malignancies ishighlighted, and evidence is provided that, apart frominternal tandem duplications and mutations, FLT3 can beactivated by translocations.