Myeloid neoplasma with eosinophilia (MLN-Eo) with rearrangement of FIP1L1-PDGFRAD72.1, C47.5

Myeloid neoplasms with eosinophilia are a clinically, morphologically, genetically, and prognostically heterogeneous group of clonal diseases characterized as follows:

• Initially, a persistent proliferation of clonal eosinophilic granulocytes in the peripheral blood.
• a hypercellular bone marrow
• if necessary, splenomegaly (Valent Pet al. 2012).

In morphology, the assessment of qualitative and quantitative changes in the non-eosinophil series (megakaryocytes, monocytes, mast cells, blasts) and bone marrow fibrosis is significant. By means of molecular genetic investigations, cytogenetic aberrations (e.g. reciprocal translocation, deletion, inversion, trisomy, complex karyotype), rearrangements of genes (FISH analysis), fusion genes (FISH analysis, RT-PCR) or mutations (allele-specific PCR, NGS) are included in the diagnosis. The causative genetic aberrations are characterized by a varying risk of progression into a myeloid or lymphoid blast phase (with a correspondingly unfavorable prognosis).

m:w = 9:1.

FIP1L1-PDGFRA positive MLN-Eo can occur in all age groups, the main age of manifestation is between 20 and 50 years of age.

IP1L1-PDGFRA is associated with eosinophilia in >95% of patients. The vast majority of patients are diagnosed in chronic phase of MPN, rarely in blast phase. This can be myeloid (medullary blast phase, extramedullary myelosarcoma) or lymphoid ("T-lymphoblastic lymphoma" = extramedullary lymphoid blast phase) differentiation (Metzgeroth G et al. (2007). In addition to the frequently encountered splenomegaly, potentially life-threatening organ manifestations due to eosinophilia may be present, primarily cardiac, e.g. endomyocardial fibrosis, thrombosis, cardiomyopathy. The bone marrow is hypercellular, usually accompanied by fibrosis and an increase in mast cells.

S.u. Myeloid neoplasms with eosinophilia

Peripheral blood is sufficient for the detection of "Myeloid neoplasia with eosinophilia (MLN-Eo) with rearrangement of FIP1L1-PDGFRA" (PCR directly detects the fusion gene, FISH analysis detects the deletion of the CHIC2 gene, which is located between FIP1L1 and PDGFRA).