New WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues

Atypical Chronic Myeloid Leukemia, BCR-ABL1–Negative

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The ASCO Post is pleased to present Hematology Expert Review, an ongoing feature that quizzes readers on issues in hematology. In this installment, Drs. Abutalib and Medeiros explore the recently updated World Health Organization (WHO) classification of hematopoietic and lymphoid tissue malignancies, focusing on atypical, BCR-ABL1–negative chronic myeloid leukemia. For each quiz question that follows, select the one best answer. The correct answers and accompanying discussions appear below.

Question 1

Which statement about epidemiology and clinical features of atypical chronic myeloid leukemia (CML) is correct?

A. Atypical CML is primarily a disease of younger (age < 60 years) adults.

B. Peripheral blood is occasionally involved with abnormal circulating cells in atypical CML.

C. Symptoms of atypical CML may be related to anemia and thrombocytopenia.

Question 2 

Which statement about microscopy in atypical CML is correct?

A. Dysgranulopoiesis is one of the diagnostic features of atypical CML.

B. Dysplasia in the megakaryocytic lineages is always present in atypical CML. 

C. Peripheral blood basophil count is not part of the diagnostic criteria for atypical CML. 

Question 3

Which statement about diagnostic criteria in atypical CML is correct?

A. The diagnostic criteria for atypical CML include monocytes constituting < 15% of the peripheral blood leukocytes.

B. Bone marrow cellularity is usually normal in atypical CML.

C. The WHO criteria for polycythemia vera should be excluded to make a correct diagnosis of atypical CML.

Question 4

Which statement about cytochemistry and immunophenotype in atypical CML is correct?

A. There are no specific cytochemical abnormalities in atypical CML.

B. Identification of specific immunophenotypic characteristics is an important diagnostic method for atypical CML.

C. Immunohistochemistry staining with CD14 or CD68R antibody on a significant number of bone marrow cells should favor a diagnosis of atypical CML. 

Question 5

Which statement about genetic profiling in atypical CML is correct?

A. The presence of the PCM1-JAK2 fusion gene favors diagnosis of atypical CML.

B. CSF3R mutation is uncommon in atypical CML.

C. SETBP1 mutation is uncommon in atypical CML.

Question 6

Which statement about prognosis in atypical CML is correct? 

A. Due to a lack of better treatment, most patients die from spleen rupture in atypical CML.

B. A white blood cell count > 25 × 109/L is one of the adverse prognostic findings in patients with atypical CML.

C. Patients with atypical CML who undergo allogeneic hematopoietic cell transplantation may have better outcomes. 


Syed A. Abutalib, MD

Syed A. Abutalib, MD

L. Jeffrey Medeiros, MD

L. Jeffrey Medeiros, MD

Dr. Abutalib is Assistant Director, Hematology and Hematopoietic Cell Transplantation Director, Hematopoietic Cell Transplant Apheresis Service, and Leader, Hematology Malignancy Program, Cancer Treatment Centers of America, Zion, Illinois. Dr. Medeiros is Professor and Chair, Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston.

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Answers to Hematology Expert Review Questions

Question 1 

Which statement about epidemiology and clinical features of atypical CML is correct?

Correct answer: C. Symptoms of atypical CML may be related to anemia and thrombocytopenia.

Expert Perspective
The exact incidence of atypical CML is unknown, but the median patient age at diagnosis is ...