| Session: Myelodysplastic syndrome |
| Case number: 215 |
Submitter(s): Anamaria Andrei, Bdeir Rabei, Anwar Mohamed, Palutke Margarita.
Clinical history
An 81 year old woman presented with fatigue and bruising and was found to have pancytopenia with 17% blasts in the peripheral blood. Bone marrow aspiration and biopsy were preformed and a diagnosis of acute leukemia arising from a myelodysplasic syndrome was made. Because of the advanced age and poor health status the patient has been treated with regular blood transfusions but no chemotherapy. She is still alive 9 months after initial presentation.
Details of gross/microscopic pathology:
The bome marrow biopsy showed a packed marrow. There were two major cell populations: blasts and large erythroblastic islands. Mature myeloid cells and megakaryocytes were decreased. Morphologically there were two distinct populations of blasts: blasts, some with cytoplasmic granules and erythrophagocytosis and myeloperoxidase positivity and blasts without granules with prominent cytoplasmic vacuoles which were Oil Red O positive. These cells were myeloperoxidase negative. Erythroblasts were dysplastic and abundant.
Immunophenotype (flow cytometry/immunohistochemistry):
Flow cytometric analysis showed two distinct populations of blasts. 36% were lymphoid: CD45, CD19, CD10, CD34, TdT and HLA-DR positive. 23% of blasts were myeloid, CD45 and TdT negative, CD117, CD34, HLA-DR, and myeloperoxidase positive.
Cytogenetics:
Cytogenetic analysis showed trisomy 8 in 14 of 20 metaphase cells. No additional abnormality was found.
Molecular analysis:
FISH analysis for trisomy 8 in destained and unstained bone marrow smears was performed. It was attempted to distinguish the two blast populations by the presence or absence of characteristic vacuoles. In most of the blasts wiith vacuoles there were only two signals. Repeat analysis will be performed.
Interesting feature(s) of submitted case:
Bilineal acute leukemias are rare. In this case of myelodysplastic syndrome, a stem cell disorder, a case could be made that there is a common stem cell for myeloid and B-lymphocytic lineages as can also be seen in chronic myelogenous leukemia. However, there are blasts with both two and three signals for chromosome 8. The hypothesis that the original stem cell did not have trisomy 8 and that this feature was acquired later by the myeloid but not the lymphoid line is also possible.
Proposed diagnosis:
Bilineal acute leukemia, myeloid and B-lymphocytic, arising from a myelodysplastic syndrome.
Panel diagnosis:
Acute bilineal leukemia
Comments:
Panel comment: History of myelodysplastic syndrome is not well documented
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