| Session: Extramedullary manifestation of neoplastic myeloid disorder |
| Case number: 012 |
Submitter(s): Annette S. Kim, Steven Goldstein, Adam Bagg.
Clinical history
A 72-year-old man was diagnosed with CML, chronic phase, in February 2006 (WBC 426.9, Hgb 11.1, Plt 92). The patient was treated with imatinib and achieved hematologic remission (WBC 6.0, Hgb 11.4, Plt 86) three months later. Pancytopenia (WBC 1.7, Hgb 11.6, Plt 37) developed the following month, leading to the discontinuation of imatinib However, one month later the patient presented with an enlarged left supraclavicular lymph node. Excisional biopsy showed precursor T cell lymphoblastic leukemia/lymphoma. A staging bone marrow and CBC demonstrated evidence of neither precursor T lymphoblastic leukemia nor chronic myelogenous leukemia. The patient was subsequently treated with systemic chemotherapy with good response.
Details of gross/microscopic pathology:
H&E stained sections from a formalin-fixed specimen revealed a enlarged left supraclavicular lymph node (1.5 cm) partially effaced by a diffuse infiltrate with scattered subcortical residual germinal centers. The infiltrate was composed of numerous medium sized blasts with large oval to irregular nuclei, vesicular chromatin, inconspicuous nucleoli, and scant cytoplasm.
Immunophenotype (flow cytometry/immunohistochemistry):
Paraffin immunohistochemistry demonstrated that the neoplastic cells were CD2-, CD3-, CD5+, CD7+, CD34+, and TdT+, indicative of a precursor T lymphoblastic lymphoma.
Cytogenetics:
Cytogenetics performed on the bone marrow demonstrated a complex karyotype: 46, XY, t(9;22) (q34;q11.2) [21]/ 59, XXYY, idem, add (1) (p32), +4, +6, +8, add (9) (p13), +10, +11, +14, +21, +22, [cp16]/ 46, XY [18].
Molecular analysis:
RT-PCR identified the presence of the e14a2 BCR/ABL1 fusion transcript in both the lymph node as well as the concurrent bone marrow specimen.
The lymph node was positive for a monoclonal TCR-gamma chain rearrangement. Although there was no morphologic evidence of precursor T lymphoblastic leukemia/lymphoma, peripheral blood and bone marrow were positive for the identical monoclonal peak on capillary electrophoresis.
Interesting feature(s) of submitted case:
The salient features that distinguish this case from the traditional progression of CML to blast crisis are: (1) the sudden nature of the blast crisis following complete hematologic remission and recent cessation of imatinib; (2) the T-lymphoid rather than B-lymphoid or myeloid nature of the blasts; and (3), the essentially exclusive extramedullary presentation of the blast crisis.
Proposed diagnosis:
Chronic myelogenous leukemia in sudden blast crisis with an exclusively extramedullary presentation of precursor T lymphoblastic lymphoma.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Stains performed by the panel: CD1a+, CD3+, CD117-, TdT 10%, MPO-, lysozyme-, CD163
PowerPoint:
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