Submitter(s): Annette H. Schmitt-Graeff, Christoph Walz, Georgia Metzgeroth, Andreas Reiter. Clinical history This male patient presented with night swets and weight loss. The white cell count was 7 x 109/L with an eosinophilia of 2.7 x 109/L. The platelets were 171 x 109/L, the hemoglobin 12.9.0 g/dL.The level of serum tryptase was slightly elevated. Hydroxyurea was started. Four months later, cardiac failure developed. Details of gross/microscopic pathology: The trephine biopsy showed architectural disturbed hypercellular marrow spaces with an increase in eosinophilic precursors, a left shift of granulopoiesis and focal aggregates of promonocytes and monoblasts. Megakarycytic dysplasia included the presence of hyper- and hypolobulated nuclei. Spindel-shaped mast cells were loosely scattered between the hematopoietic cells. Silver impregnation revealed reticulin fibrosis grade 2. Immunophenotype (flow cytometry/immunohistochemistry): Increased numbers of megakaryocytes were demonstrated by CD41 and CD61 immunoreactivity. The granulocytic lineage was strongly positive for myeloperoxidase. The CD34 immunostain showed foci of atypical localized marrow blast cells/precursors accounting for less than 10% of nucleated cells. There was evidence of an abnormal mast cell phenotype with coexpression of tryptase, CD117, CD2 and CD25. The lymphoid nodules were predominantly composed of T-cell. Cytogenetics: Molecular analysis: RT-PCR: PDGFR-Beta rearrangement Absence of BCR-ABL translocation or JAK2 V617F. Interesting feature(s) of submitted case: This case shows that deregulation and constitutive activation of the receptor tyrosine kinase PDGFRB may be associated with an atypical myeloproliferative disorder (MPD) with predominant eosinophilia, multilineage dysplasia with blast excess and mastocytosis. Interestingly, the bone marrow histology and immunohistology showed some features which were quite similar to the FIP11L1-PDGFRA-rearranged MPD. Common features included eosinophilia, the presence of abnormal CD2 CD25 positive mast cells and reticulin fibrosis. The identification of the disease-causing mutations are important for a targeted therapy with a tyrosine-kinase inhibitor in patients eosinophilic disorders. Proposed diagnosis: PDGFRB-rearranged eosinophilic disorder (atypical MPD). Panel diagnosis: agree with proposed diagnosis Comments: Panel comment: Additional data including complete PB differential, bone marrow differential count and review of bone marrow aspirate smear are necessary. Images: Back to Top Back to Cases by Session Back to Cases by Contact Submitter |