MLT GlobeHematology: WBC disorders & leukemias – page 6
145 Hematology MCQs on WBC disorders & leukemias with answers and explanations.
Six years after alkylating-agent chemotherapy for breast cancer, a woman has pancytopenia, dysplasia and loss of chromosome 7. The best category is:
Alkylating agents typically cause myeloid neoplasms 5–10 years later with dysplasia and -5/-7 abnormalities. Topoisomerase II inhibitor–related cases appear sooner, often with KMT2A rearrangement.
A JAK2- and CALR-negative patient with essential thrombocythemia should next be tested for mutations in:
The three driver genes of ET and primary myelofibrosis are JAK2, CALR and MPL (exon 10, e.g., W515). BCR::ABL1 should be excluded by fusion testing, but kinase-domain sequencing is for TKI resistance.
Using WHO 5th edition criteria, which hemoglobin level in a man meets the major hemoglobin criterion for polycythemia vera?
WHO uses Hb >165 g/L in men and >160 g/L in women (or Hct >49%/48%). The older 185 g/L value was from earlier criteria and missed early disease.
Hypereosinophilia, used in the work-up of eosinophilic disorders, is defined as a blood eosinophil count of at least:
Hypereosinophilia is ≥1.5 × 10^9/L on two tests separated in time (or tissue hypereosinophilia). Eosinophilia starts above about 0.5 × 10^9/L.
A 2-year-old has splenomegaly, monocytes 3 × 10^9/L, raised hemoglobin F, circulating myeloid precursors and a PTPN11 mutation. No BCR::ABL1 is found. The likely diagnosis is:
JMML is a childhood myeloid neoplasm driven by RAS-pathway mutations (PTPN11, NRAS, KRAS, NF1, CBL), with monocytosis ≥1 × 10^9/L and often high HbF; WHO 5th edition places it among the myeloproliferative neoplasms (the ICC keeps it as MDS/MPN). CMML occurs in older adults.
A child has lytic skull lesions. Biopsy shows cells with grooved nuclei positive for CD1a and langerin (CD207). The diagnosis is:
Langerhans cells are CD1a+, S100+ and langerin+, with Birbeck granules; many cases carry BRAF V600E. Myeloma causes lytic lesions but is rare in children and shows plasma cells.
A febrile child has pancytopenia, splenomegaly, ferritin above 10 000 µg/L, high triglycerides, low fibrinogen and marrow macrophages engulfing blood cells. The likely diagnosis is:
HLH is uncontrolled macrophage/T-cell activation with fever, cytopenias, very high ferritin, hypertriglyceridemia, low fibrinogen and hemophagocytosis; soluble CD25 is also high. Transfusion iron overload does not cause fever and hemophagocytosis.
A boy with recurrent skin abscesses and liver abscesses with Staphylococcus and Aspergillus has neutrophils that show no fluorescence shift on the dihydrorhodamine (DHR) flow test. The disorder is:
The DHR test measures NADPH oxidase activity; absent respiratory burst confirms chronic granulomatous disease. MPO deficiency gives a normal DHR response and is usually mild.
An infant with delayed separation of the umbilical cord, severe infections without pus and persistent neutrophilia most likely lacks which molecule?
Leukocyte adhesion deficiency type I lacks CD18, so neutrophils cannot adhere and leave vessels, causing high blood neutrophil counts and no pus at sites of infection. CD55 loss is seen in PNH.
A child has fever, mouth ulcers and neutropenia that recur about every 21 days, with normal counts between episodes. The likely gene involved is:
Cyclic neutropenia is caused by ELANE (neutrophil elastase) mutations, giving neutrophil nadirs about every 3 weeks. LYST mutation causes Chédiak-Higashi syndrome.
On a CD45 versus side-scatter flow cytometry plot of marrow, where do myeloblasts usually lie?
Blasts have weaker CD45 than mature leukocytes and little granularity, so they sit in the 'blast gate'. Bright CD45 with low side scatter is the lymphocyte region; high side scatter marks granulocytes.
Naphthol AS-D chloroacetate esterase (specific esterase) is positive mainly in:
Chloroacetate esterase marks neutrophil lineage cells and mast cells. Monocytic cells are shown by non-specific (alpha-naphthyl) esterase, which is fluoride-inhibited.
An absolute basophilia on the blood film is most characteristic of:
Basophilia is a typical feature of CML and other myeloproliferative neoplasms. Bacterial infection causes neutrophilia, not basophilia.
Auer rods are formed from:
Auer rods are rod-shaped fusions of primary granules and are myeloperoxidase positive. They indicate a myeloid lineage.
The most common cause of serious infections in chronic lymphocytic leukemia is:
CLL cells do not make normal antibodies, and normal B-cell function is suppressed. The resulting low immunoglobulin levels lead to recurrent bacterial infections.
The large reactive lymphocytes seen in infectious mononucleosis are mainly:
EBV infects B cells, and the reactive lymphocytes on the film are mostly CD8-positive T cells attacking those infected cells.
In the WHO 5th edition, the entity formerly called RARS-T, now MDS/MPN with SF3B1 mutation and thrombocytosis, belongs to which category?
It combines dysplastic erythropoiesis with ring sideroblasts and SF3B1 mutation with thrombocytosis of MPN type, so it sits in the overlap MDS/MPN group.
Under the WHO 5th edition classification, juvenile myelomonocytic leukemia (JMML) is placed among:
WHO-HAEM5 moved JMML into the MPN category because of its RAS-pathway-driven proliferative nature. Older editions (and the ICC) list it as MDS/MPN.
Which is NOT a recognized late complication of hematopoietic stem cell transplantation with total body irradiation?
Irradiation and conditioning drugs cause cataracts, leukoencephalopathy and anthracycline-related cardiomyopathy. Lung injury after transplant is usually pneumonitis or bronchiolitis obliterans, not emphysema.
In the WHO classification, chronic eosinophilic leukemia is grouped with:
Chronic eosinophilic leukemia is a clonal proliferation of eosinophil precursors listed with the MPNs. Eosinophilia with defined tyrosine kinase fusions forms a separate group.