Spectrum of associated clonal hematologic non-mast cell lineage disorders occurring in patients with systemic mastocytosis.

Systemic mastocytosis (SM) is a myeloproliferative disease affecting multipotent and/or mast cell-committed hematopoietic progenitor cells. In a significant subgroup of patients (10-35%), an associated clonal hematologic non-mast cell lineage disorder (AHNMD) occurs. These AHNMDs can be classified according to recently established WHO criteria. Most AHNMDs resemble myeloid malignancies such as acute myeloid leukemia, myeloproliferative disorders or myelodysplastic syndromes. In only a few cases, lymphoproliferative disorders are diagnosed. Patients with SM-AHNMD have a less favorable prognosis concerning survival when compared to indolent SM. No general guidelines for the treatment of patients with SM-AHNMD have been established so far. A reasonable straightforward approach may be to treat the AHNMD in those patients in the same way as if no coexisting SM exists.