MLT GlobeHematology: WBC disorders & leukemias
145 Hematology MCQs on WBC disorders & leukemias with answers and explanations.
A teenager with fever, sore throat and many reactive lymphocytes has a positive rapid heterophile (Monospot) test. What is the diagnosis?
Monospot detects heterophile antibodies made in Epstein–Barr virus infectious mononucleosis. Leukemias show blasts, not reactive lymphocytes with a positive heterophile test.
Detection of the BCR::ABL1 fusion from t(9;22) is key to diagnosing which disorder?
The Philadelphia chromosome, t(9;22), produces BCR::ABL1 and defines CML. It can also occur in some ALL, but CML is the disease it characterizes.
In which age group is chronic lymphocytic leukemia most often diagnosed?
CLL is the most common leukemia in Western adults, with a median diagnosis age around 70; it is extremely rare in children, where ALL predominates.
Which blood finding is characteristic of chronic lymphocytic leukemia?
CLL requires at least 5 × 10^9/L clonal B lymphocytes, which are small and mature-looking. Blasts suggest acute leukemia.
A film from an elderly patient shows many small mature lymphocytes and numerous 'smudge' cells. Which disorder is most likely?
CLL cells are fragile and rupture during spreading, forming smudge cells; their chromatin is clumped in a 'soccer-ball' pattern. AML shows blasts; mononucleosis shows reactive lymphocytes.
A CBC reports a total leukocyte count of 18 × 10^9/L in an adult. What term describes this?
Leukocytosis is a WBC count above the reference interval (about 11 × 10^9/L in adults). Leukopenia is a low count; erythrocytosis concerns red cells.
The JAK2 V617F mutation is found in more than 95% of patients with which disorder?
JAK2 V617F or exon 12 mutations are found in nearly all PV cases and in about half of ET and PMF. CML is defined by BCR::ABL1.
A CBC shows Hb 7.8 g/dL, WBC 2.1 × 10^9/L and platelets 40 × 10^9/L. This combination is termed:
Reduction of all three cell lines (red cells, leukocytes and platelets) is pancytopenia. A leukoerythroblastic picture means immature myeloid and nucleated red cells in blood.
A 4-year-old presents with pallor, bruising and bone pain, and blasts are seen on the smear. Statistically, the most likely diagnosis is:
ALL is the commonest childhood cancer, peaking at 2–5 years, mostly of B-cell type. AML is more common in adults, and CLL essentially does not occur in children.
Which leukemia is the most common in older adults in Western countries, usually after age 60?
CLL is the commonest adult leukemia in Western populations, with median age around 70. CML peaks in middle age; ALL is mainly a childhood disease.
Which inclusion, when seen in blasts on a peripheral smear, most strongly points to a myeloid rather than a lymphoid acute leukemia?
Auer rods are rod-shaped fusions of primary (azurophilic) granules containing myeloperoxidase. They are found only in myeloid blasts, so their presence rules in AML and effectively rules out ALL.
Which cytochemical result best separates AML from ALL?
Myeloperoxidase (and Sudan black B) are positive in myeloblasts and negative in lymphoblasts. A threshold of 3% or more MPO-positive blasts supports a myeloid lineage.
Terminal deoxynucleotidyl transferase (TdT) in blasts is a marker of:
TdT is a DNA polymerase active in immature B and T lymphocytes. TdT-positive blasts support ALL or lymphoblastic lymphoma; mature lymphoid cancers such as CLL are TdT negative.
The most common leukemia in children is:
B-ALL makes up about three-quarters of childhood leukemias, with a peak at 2 to 5 years. CLL is the most common leukemia in older adults in Western countries.
Rouleaux on the smear, a monoclonal band on serum protein electrophoresis and more than 10% clonal plasma cells in the marrow indicate:
Excess monoclonal immunoglobulin coats red cells and causes rouleaux. A monoclonal (M) protein plus at least 10% clonal marrow plasma cells, with end-organ damage, defines multiple myeloma.
Which peripheral blood picture is most typical of chronic-phase chronic myeloid leukemia?
Chronic-phase CML shows marked leukocytosis with a full spectrum of maturing granulocytes (myelocyte and segmented peaks) and basophilia. Toxic changes point to infection, not CML.
Follicular lymphoma is characteristically associated with which translocation?
t(14;18) places BCL2 under the IGH enhancer, blocking apoptosis. t(8;14) is Burkitt and t(2;5) is anaplastic large cell lymphoma.
Classic Reed-Sternberg cells of classic Hodgkin lymphoma typically show which immunophenotype?
Hodgkin/Reed-Sternberg cells are usually CD30+ and CD15+ with loss of CD45. Nodular lymphocyte-predominant cells are CD20+ and CD45+.
A Caribbean-born adult has hypercalcemia, skin lesions and circulating lymphocytes with multilobed 'flower-shaped' nuclei. The associated virus is:
Adult T-cell leukemia/lymphoma is caused by HTLV-1 and shows CD4+ 'flower cells' and hypercalcemia. EBV is linked to Burkitt and Hodgkin lymphoma.
Imatinib controls chronic myeloid leukemia mainly by:
Imatinib is a tyrosine kinase inhibitor that competes with ATP at the ABL1 kinase domain, stopping the constant signaling of BCR::ABL1. Differentiation therapy (ATRA) is used in acute promyelocytic leukemia, not CML.