| Session: Myelodysplastic syndrome |
| Case number: 075 |
Submitter(s): Cristina Montalvo, Eugenio I. Banez.
Clinical history
The patient is a 64 y.o. diabetic male who presented with a 2 mo. history of decreased exercise tolerance. Splenomegaly was absent. The CBC demonstrated a pancytopenia: WBC 2,000/uL (55% neutrophils, 32% lymphocytes, 12% monocytes, 1% eosinophils), RBC 1.8 x 106/uL, Hgb 6.8 g/dL, MCV 106 fL, and platelets 22,000/uL.
Details of gross/microscopic pathology:
The peripheral smear showed anisocytosis but no poikilocytosis of red cells. The WBCs were without dyspoiesis.
A formalin-fixed bone marrow biopsy demonstrated hypercellular, fibrotic marrow with panhyperplasia. The megakaryocytic component was especially prominent because of the pronounced atypia (clustering, hyperchromasia and pyknosis). Immature cells were increased, and few lymphoid aggregates were present. An aspirate smear was not obtained, only touch preps. Dyserythropoiesis was moderate. Myeloid precursors were insufficient for evaluation. Two megakaryoblasts were identified; blasts were <1% of cells.[figure1][figure2][figure3][figure4][figure5]
Immunophenotype (flow cytometry/immunohistochemistry):
The CD 34 stain showed increased blasts, ~10%.[figure6]Factor 8 stained the megakaryocytes and numerous smaller cells.[figure7] Staining with MPO elucidated the increased myeloid population,[figure8]and the reticulin stain demonstrated an increase in reticulin fibrosis.[figure9]The iron stain showed increased iron stores but no ringed sideroblasts.
The sample submitted for flow was hemodilute.
Cytogenetics:
An abnormal clone with multiple abnormalities was identified: monosomy 2,5,7, and 15; trisomy 8; unbalanced translocation between 17p and 2q; additional chromosomic material of unknown origin replacing 7q and on 17q and 12p; and 2 to 5 marker chromosomes of unknown origin.
Molecular analysis:
Interesting feature(s) of submitted case:
This case illustrates a remarkable constellation of findings infrequently encountered in the marrow: panhyperplasia associated with distinct megakaryocytic atypia, fibrosis and increased blasts. The work-up is further complicated by the absence of adequate aspirate smears and a satisfactory flow sample. The differential diagnosis of myeloid disorders with myelofibrosis includes: myelodysplastic syndrome with fibrosis, acute megakaryoblastic leukemia, acute panmyelosis with myelofibrosis, and the chronic myeloproliferative disorders.
Proposed diagnosis:
Based on the absence of splenomegaly and leukoerythroblastic blood smear with poikilocytosis, a CMPD is unlikely. Without the establishment of >20% blasts, the diagnosis of AML cannot be substantiated. Also, AML-M7 generally manifests a predominantly megakaryoblastic proliferation with a higher percentage of blasts in the marrow and peripheral blood. The most difficult distinction is between MDS with fibrosis and APMF, which share numerous clinical and morphologic features. The duration of the pancytopenia in this patient cannot reliably be ascertained. However, the cytogenetic findings (-5, -7, +8, plus other complex abnormalities) support the diagnosis of a high-grade MDS with fibrosis.
Panel diagnosis:
agree with proposed differential diagnosis of MDS with fibrosis vs. APMF
Comments:
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