The ASCO Post is pleased to introduce “Hematology Expert Review,” a new feature including a case report detailing a particular hematologic condition followed by questions. Answers to each question appear with expert commentary. In this first installment, we present two cases of older men with myeloid neoplasm.
Case 1: Prerequisites for classification of myeloid neoplasm by World Health Organization (WHO) classification of tumors of the hematopoietic and lymphoid tissues
A 65-year-old man is being evaluated for a myeloid neoplasm due to a recent development of pancytopenia. A manual 200-cell leukocyte differential of the peripheral blood shows a blast count of 10%. A bone marrow biopsy and aspirate are obtained from the same posterior iliac site. A portion of the marrow aspirate is sent for flow cytometry and cytogenetic studies.
You review the bone marrow aspirate and core biopsy with an experienced hematopathologist. There is dysplasia in one lineage, and the blast count is 45% from the 500-cell count of multiple areas of cellular bone marrow aspirate. However, the flow cytometry study reports only 15% blasts.
In this patient, which statement is the one best explanation for the discrepancy observed between the blast percentage by bone marrow aspirate visual inspection and the flow-cytometry study?
A. The bone marrow specimen for flow cytometry is diluted with sinusoidal or peripheral blood.
B. Flow-cytometry analyzes many more cells than the visual examination and thus is a more accurate blast measurement.
C. Flow-cytometry study may not be identifying all of the blasts in the aspirate specimen.
D. Blast cells were “lost” in the processing of the marrow aspirate for flow cytometry studies.
How can hemodilution of bone marrow aspirates best be avoided?
A. Perform a core biopsy prior to the aspirate.
B. Perform an aspirate prior to the core biopsy.
C. Collect no less than 0.4 mL of bone marrow aspirate in the first syringe for smear preparations.
D. Reposition the aspirate needle if more than 0.5 mL of marrow aspirate is required for laboratory studies.
Which of the following statements is part of the guidelines recommended by WHO (2008) for the evaluation of an initial specimen in patients suspected of having underlying myeloid neoplasms?
A. Clinical findings should not be correlated with bone marrow findings, as they may lead to bias on the part of the hematopathologist.
B. Cytogenetic and molecular genetic studies are not required.
C. At least 500 bone marrow nucleated cells should be counted on a cellular aspirate.
D. Flow-cytometry determination of the blast percentage can be used as a substitute for visual inspection.
Case 2: Optimal bone marrow core biopsy specimen in adults
A 60-year-old man is referred by his family practitioner for evaluation of pancytopenia and splenomegaly. Complete blood cell count and manual differential show a white blood cell count of 10,500/mL, hemoglobin of 8.1 g/dL, and a platelet count of 154,000/mL. Review of the peripheral smear shows many teardrop red blood cells, small numbers of dysplastic myelocytes and metamyelocytes, and 5% blasts. Physical exam revealed splenomegaly, with no hepatic enlargement or lymphadenopathy. The clinical impression is a myeloproliferative neoplasm.
A bone marrow aspirate and core biopsy are obtained. The marrow aspirate smears show a hemodilute specimen with no marrow particles but many myeloid and erythroid precursor elements, rare dysplastic megakaryocytes, and 10% blasts. The bone marrow core biopsy was 0.4 mm in length.
What is an acceptable size of a core biopsy specimen in adults?
A. A minimum of two marrow core biopsies, each measuring 0.4 cm
B. At least 0.5 cm
C. The acceptable size of the marrow core biopsy may vary depending on the suspected diagnosis.
D. At least 1.5 cm
Syed A. Abutalib, MD, Assistant Director, Hematology & Bone Marrow Transplantation Service, Cancer Treatment Centers of America, Zion, Illinois
Frederick G. Behm, MD, Frances B. Geever Professor and Head, Department of Pathology, University of Illinois at Chicago College of Medicine, Chicago, Illinois
Case 1: Prerequisites for classification of myeloid neoplasm
Question 1: Which statement is the one best explanation for the discrepancy observed between the blast percentage by bone marrow aspirate visual inspection and the flow-cytometry study?
Correct Answer: C. Flow-cytometry study may not be ...