PA18.1-2 | Benign Leukocytosis & Leukemias — Graded Quiz

A 28-year-old woman is found incidentally to have WBC 38,000/µL during antenatal screening at 32 weeks of gestation. Differential shows 80% neutrophils. She is afebrile, hemodynamically stable, and has no clinical complaints. Repeat CBC the following day: WBC 34,000/µL. Peripheral smear shows mature neutrophils, occasional band forms (<5%), no blasts, no immature granulocytes. Leukocyte alkaline phosphatase (LAP) score is 180 (elevated). Which is the most accurate interpretation?

A 16-year-old girl presents with fever, fatigue, sore throat, and generalised lymphadenopathy of 2 weeks duration. She has posterior cervical and axillary lymphadenopathy and mild splenomegaly. CBC: WBC 18,000/µL with 70% lymphocytes, 20% atypical lymphocytes, Hb 11.8 g/dL, platelets 130 × 10⁹/L. The heterophile antibody test (Monospot) is positive. She is started on amoxicillin by her general practitioner for presumed streptococcal tonsillitis. Two days later, she develops a generalised maculopapular rash. Which is the most accurate explanation for the rash?

A 55-year-old male with a 20 pack-year smoking history has a WBC of 22,000/µL with 88% neutrophils on a routine health check. He is afebrile, has no infections, no lymphadenopathy, and no splenomegaly. CRP is normal. He takes no medications. A peripheral smear shows mature segmented neutrophils without left shift, toxic granulation, or Döhle bodies. Which is the most likely mechanism and best next management step?

A 60-year-old man presents with progressive abdominal distension, early satiety, and 8 kg weight loss over 4 months. He has a massive spleen palpable 14 cm below the costal margin. CBC: Hb 9.8 g/dL, WBC 180,000/µL, platelets 620 × 10⁹/L. Peripheral smear shows the full myeloid spectrum (blasts 2%, promyelocytes 4%, myelocytes 18%, metamyelocytes 12%, bands 8%, mature neutrophils 50%) with prominent basophilia (8%) and eosinophilia (5%). The leukocyte alkaline phosphatase (LAP) score is 12 (markedly low). Which molecular test confirms the diagnosis, and what does it detect?

A 35-year-old man with CML on imatinib (400 mg/day) achieves a major molecular response (MMR: BCR-ABL1 IS <0.1%) at 12 months. He is now 4 years into therapy with sustained deep molecular response (BCR-ABL1 <0.01% for 2 years). He asks about stopping imatinib. His haematologist explains the concept of 'treatment-free remission.' One year after planned imatinib discontinuation, the patient's BCR-ABL1 transcript becomes detectable at 0.5% IS. What is the most appropriate clinical response?

A 5-year-old girl presents with 3 weeks of pallor, easy bruising, and bone pain. CBC: Hb 7.2 g/dL, WBC 4,500/µL, platelets 38 × 10⁹/L. Peripheral smear shows 35% blasts that are small, with scant cytoplasm, fine chromatin, and inconspicuous nucleoli. Bone marrow aspirate: 92% lymphoblasts. Flow cytometry: TdT+, CD10+, CD19+, CD22+, CD34+, CD3−, MPO−. Cytogenetics: t(12;21)(p13;q22). What is the prognostic significance of this cytogenetic finding?

A 45-year-old man presents acutely with fever, gum bleeding, and diffuse petechiae for 5 days. CBC: Hb 8.4 g/dL, WBC 62,000/µL, platelets 24 × 10⁹/L. Peripheral smear shows 80% large blasts with Auer rods. D-dimer is markedly elevated (>8,000 ng/mL), fibrinogen is 0.9 g/L (low), PT and aPTT are prolonged. He is bleeding from venepuncture sites. Which AML variant is MOST likely, and what is the immediate pharmacological priority?

A 70-year-old man is incidentally found to have lymphocytosis of 42,000/µL on routine CBC. He is asymptomatic with no lymphadenopathy, no splenomegaly, and no B symptoms. His CBC otherwise shows Hb 13.1 g/dL, platelets 190 × 10⁹/L. Peripheral smear shows small, mature-appearing lymphocytes with smudge cells. Flow cytometry: CD5+, CD19+, CD20 (dim), CD23+, FMC7−, surface IgM (dim). Cytogenetics: del(13q). Which statement about his management is most appropriate at this time?

A 65-year-old man with known CLL (Rai stage II, under watchful waiting for 3 years) presents with 6 weeks of rapidly enlarging right cervical lymph node, fever, and drenching night sweats. On examination, the node is 5 cm, firm, and non-tender. CBC: lymphocyte count has actually fallen from baseline 48,000 to 22,000/µL. LDH is 2,100 U/L. Excision biopsy shows large B-cell lymphoma histology with a diffuse pattern, CD20+, CD10−, BCL-2+, MUM1+. Which diagnosis and its mechanism is most accurate?

A 3rd-year MBBS student is reviewing a bone marrow aspirate from a 58-year-old with pancytopenia. The report states: 'Marrow is hypercellular; 85% of cells are uniform, medium-sized lymphoid cells with a round nucleus, clumped chromatin, and scant cytoplasm; CD5+, CD19+, CD23+.' The student concludes this is consistent with CLL marrow infiltration. However, the attending haematologist points out that this finding must be distinguished from a 'dry tap' finding in a myelofibrosis case. Which statement most accurately explains why CLL marrow infiltration rarely causes a 'dry tap'?

A medical student is presented with a peripheral blood smear from a patient with acute leukaemia. She observes large cells with a high nuclear-to-cytoplasmic ratio, prominent nucleoli, fine chromatin, and azurophilic granules in the cytoplasm. One cell has a distinctive pink rod-shaped intracytoplasmic inclusion. The myeloperoxidase (MPO) stain is strongly positive. Which cell type and diagnosis do these findings confirm, and what is the prognostic significance of the intracytoplasmic inclusion?

A pathology tutorial shows a bone marrow trephine biopsy section stained with H&E. The marrow is hypercellular, with sheets of immature cells replacing all normal haematopoietic elements and fat spaces. The cells are medium-to-large, with round nuclei, dispersed chromatin, prominent single nucleoli, and scant basophilic cytoplasm. An MPO immunostain of the trephine is negative. TdT immunostain is strongly positive in the neoplastic cells. What is the most likely diagnosis, and which lineage do these cells belong to?