| Session: Chronic myelogenous leukemia |
| Case number: 137 |
Submitter(s): Neerja Vajpayee, Constance Stein, Bernard Poeisz, Robert E. Hutchison.
Clinical history
A 30 year old man without any significant prior history presented to the emergency room with groin pain and inguinal lymphadenopathy.
CBC results
Hemoglobin 15.5 gm/dL, WBC of 300 k/uL and platelet count 25 K/uL
Differential count (200 cells)
7% blasts, 10% promyelocytes, 44% myelocytes, 4% metamyelocytes, 5% bands, 20% neutrophils, 4% eosinophils, 2% basophils, 3% lymphocytes and 1% monocytes. (Figure1)
Details of gross/microscopic pathology:
Bone marrow aspirate (Wright-Giemsa stained smears), 500 cell differential count showed 8.4% blasts (Figure2).
Bone marow biopsy section (B5 fixed, H and E stain) revealed large blast aggregates in a background of markedly hypercellular marrow with prominent myeloid hyperplasia (Figure3).
Excisional biopsy of the inguinal node (B5 fixed, H and E stain) showed near complete replacement by sheets of blasts (Figure4).
Immunophenotype (flow cytometry/immunohistochemistry):
Immunostains were done on the lymph node:
A majority of the cells were positive with CD3 (Figure5). Occasional cells were MPO positive (Figure6) and Tdt was positive (Figure7) in numerous but scattered cell nuclei.
Flow cytometry (Figure8) performed on both the nodal tissue and the bone marrow aspirate revealed blasts expressing
T-cell markers: CD7, CD2, CD5, cCD3; surface CD3, CD4 and CD8 were negative
Myeloid markers: CD33 (partial), CD13 (partial)
B-cell marker: CD79a
Others: CD34 and Tdt (weak and partial).
Cytogenetics:
Karyotype: 46 XY with a complex rearrangement between the long arms of chromosome 9, 22 and 13 in all cells indicative of a 3 way translocation.
FISH revealed a pattern consistent with t(9;22) in most cells. An additional Philadelphia chromosome was noted in 4% of cells and 6% showed a variant signal pattern.
Molecular analysis:
Interesting feature(s) of submitted case:
Blast transformation of CML at presentation in an extramedullary site is rare and precursor T-lymphoblastic transformation is also rare.
This combination is extremely unusual.
Proposed diagnosis:
Chronic myelogenous leukemia initially presenting with precursor T-lymphoblastic transformation in an extramedullary site.
Panel diagnosis:
More likely CML in T-cell/myeloid transformation
Comments:
Stains performed by the panel: neoplastic cells positive for CD33, CD117 (in about 30% of cells), and MPO in about 10-20% of cells. Additional information from the submitter: Karyotype and FISH done on the bone marrow sample.
PowerPoint:
Presentation Link
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