| Session: Myelodysplastic / myeloproliferative disease |
| Case number: 155 |
Submitter(s): Phuong L. Nguyen, James D. Hoyer, Janice M. Hodnefield, Curtis A. Hanson.
Clinical history
The patient is a 58-year-old woman with a five-month history of 10-pound weight loss, fatigue, and bruising. Prior medical/surgical and family history is non-contributory. Her current medication consists only of Prilosec. The physical exam reveals no hepatosplenomegaly, lymphadenopathy, or skin lesions. Laboratory evaluations show the following: Hgb 9.4 g/dL; RBC 3.19 x 1012/L; MCV 87.8 fL; RDW 16.2%; WBC 53.4 x 10 9/L; Plt 940 x 10 9/L. The WBC differential count shows 35.0% segmented neutrophils; 12.0% lymphocytes; 4.0% metamyelocytes; 43.0% myelocytes; 6.0% blasts.
Details of gross/microscopic pathology:
The blood smear (figure 1) shows a normocytic anemia with non-specific poikilocytosis. There is a left-shifted neutrophilia with circulating blasts (6%). No absolute basophilia or eosinophilia is seen. There is a thrombocytosis with a few atypically large and hypogranular forms.
The hypercellular bone marrow aspirate shows decreased erythroid precursors, increased and left-shifted granulopoisis, and increased megakaryocytes with atypically multinucleated forms (figures 2 & 3). A 500-cell differential count shows 22.0% segmented neutrophils and bands; 3.0% metamyelocytes; 65.0% myelocytes; 1.0 promyelocytes; 3.0% blasts; 3.0% normoblasts; 1.0% monocytes; 2.0% lymphocytes.
The markedly hypercellular bone marrow biopsy (B5-fixed, decalcified) confirms the aspirate findings (figures 4 & 5). No clusters of megakaryocytes or discrete foci of blasts are noted.
Special studies: Iron stores are adequate without ringed sideroblasts. No increase in butyrate esterase- or dual esterase-positive monocytic cells is seen. Reticulin fibers are normal.
Immunophenotype (flow cytometry/immunohistochemistry):
Immunohistochemical studies of the paraffin-embedded biopsy sections confirm the presence of atypical CD61-positive megakaryocytes with abnormally disconnected nuclear lobes (figure 6) without cluster formation (figure 7). CD34-positive cells number <5%.
Cytogenetics:
Cytogenetic analysis shows trisomy 8 in each analyzed metaphase. FISH studies are negative for fusion of BCR and ABL signals.
Molecular analysis:
Molecular genetic analyses are negative for TEL/PDGFR-[beta] and FIP1L1/PDGFR-[alpha]. JAK2 mutation status is pending.
Interesting feature(s) of submitted case:
1. The predominant hematologic parameters are those of a chronic myeloproliferative disease (CMPD) with both a neutrophilia and a thrombocytosis, but the morphologic features of the megakaryocytes, in the absence of megakaryocyte clusters, are those more typically associated with myelodysplastic syndromes. Is this morphologic feature sufficient to consider this process as overlapping with a myelodysplastic process?
2. How should JAK2 mutation status, pending at this time, help in subclassifying this process? If positive, would the result override the megakaryocyte morphology and place this case in the CMPD category?
Proposed diagnosis:
Myelodysplastic/myeloproliferative disease, unclassifiable.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Additional information from the submitter: JAK2 mutation analysis could not be completed due to interferences in DNA extraction. There has not been further follow-up visit from this patient.
Images:
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Figure 6 |
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