| Session: Extramedullary manifestation of neoplastic myeloid disorder |
| Case number: 221 |
Submitter(s): Sergey D. Popov, Margarita Palutke.
Clinical history
A 5 year old boy presented with pallor, fatigue, fever, chest and joint pain in November 2006. Pneumonia was suspected. However, CT scans showed multiple bone lesions in ribs, scapula, sternum and skull. The CBC showed moderate anemia, a white count of 7,200 with 6% blasts, 1% metamyelocytes, 22% band forms, 32% PMNs, 7% monocytes, 1% eosinophils, 29% lymphocytes. Platelet count was 260,000. A bone marrow aspiration was performed and showed 47% blasts. The patient was treated for acute myelogenous leukemia on protocol AML-BFM 04 INTERIM: Cytozar, Idorubomycin, Vipezid, Mitoxantron. Second course of chemotherapy was given in January. Repeat CT scans demonstrated healing of all bone lesions.
Details of gross/microscopic pathology:
Bone marrow smears were hypercellular and showed mononuclear blasts with a high nucleus to cytoplasmic ratio, fine chromatin, nucleoli, and cytoplasmic pseudopod formation. Bone marrow biopsy was not performed.
Immunophenotype (flow cytometry/immunohistochemistry):
Flow cytometry showed that blasts were CD13, CD33, CD117, CD61 positive. They were CD2, CD3, CD5, CD19, CD79a, HLA-DR and TdT as well as myeloperoxidase negative.
Cytogenetics:
46 XY.
Molecular analysis:
No abnormalities detected.
Interesting feature(s) of submitted case:
Multiple osteolytic lesions and adjacent soft tissue tumors (megakaryoblastomas) have been described in pediatric patients with de novo acute megakaryocytic leukemia, but as a rule not in the type associated with Down syndrome which is a much milder disorder. The radiological findings may simulate those of metastatic lesions of other small round cell tumors.
Proposed diagnosis:
Acute megakaryocytic leukemia.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Panel comment: no bone marrow biopsy available; no comment on CD34 expression, or expression of megakaryocytic markers other than CD61.
Images:
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Figure 1 |
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Figure 2 |
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