Leukaemias and Myeloproliferative Neoplasms for NEET PG Pathology: ALL, AML, CLL, CML, MDS, Polycythaemia Vera

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🎯 Exam priority: Very high. Expect: a child with bone pain and blasts (ALL), Auer rods, APL treated with tretinoin, an elderly man with lymphocytosis (CLL markers), massive spleen with Philadelphia chromosome, and a leukaemoid reaction vs CML.

CBME mapping: PA 18.1–18.2.

White-Cell Counts: Low and High

• Neutropenia: below 1500/µL (lower normal in Black people); moderate 500–1000; severe < 500, when gut and mouth flora start causing infections.

• Leukaemoid reaction: neutrophils > 50,000/µL without malignant transformation — usually from another cancer or a systemic infection; it can be mimicked by CML.

The Four Leukaemias

ALL, AML, CLL and CML compared, from MSD's comparison table. Drawn by TrackNation.

• Acute leukaemias have immature blasts; chronic ones have more mature cells. Pancytopenia with blasts on the smear suggests acute leukaemia.

• ALL: commonest childhood cancer; 60% of cases in children, peak 2–5 years; TdT positive (lymphoid); can infiltrate the CNS and testes.

• AML: myeloperoxidase positive (myeloid); Auer rods are crystallised MPO granules. APL: t(15;17) PML::RARA, treated with tretinoin and arsenic trioxide.

• CLL: CD5+ B cells expressing CD5, CD19, CD20, CD23; hypogammaglobulinaemia in up to two-thirds; autoimmune haemolysis; can transform to diffuse large B-cell lymphoma (Richter).

• CML: t(9;22) — ABL from chromosome 9 fuses to BCR on 22 (Philadelphia chromosome, > 90%); low leukocyte alkaline phosphatase; rising basophils herald progression; treated with tyrosine kinase inhibitors.

Myelodysplastic and Myeloproliferative Neoplasms

• MDS: marrow failure with < 20% blasts (not enough for AML); 40–60% evolve into AML. Del(5q): severe anaemia with thrombocytosis.

• Polycythaemia vera: JAK2 (rarely CALR) mutation; aquagenic pruritus (itch after hot water); treated with phlebotomy, low-dose aspirin, ruxolitinib or interferon.

• Essential thrombocythaemia: JAK2 V617F in about 50%.

• Primary myelofibrosis: marrow fibrosis, extramedullary haematopoiesis in the spleen, teardrop and nucleated red cells.

Traps the Examiner Sets

• TdT = lymphoid (ALL); myeloperoxidase and Auer rods = myeloid (AML).

• APL: t(15;17), treated with tretinoin and arsenic.

• Leukaemoid reaction vs CML: CML has the Philadelphia chromosome and low LAP.

• Itching after a hot shower with high haemoglobin: polycythaemia vera (JAK2).

Memory Hooks & Shortcuts

Shortcuts to lock in this article's numbers and lists. Each one only re-packages facts proven above.

• 🧠 TdT = Toddler's leukaemia (ALL) — lymphoid marker

• 🧠 Auer = AML — MPO rods in myeloblasts

• 🧠 APL: 15 + 17, Retinoic and arsenic Rescue — t(15;17), tretinoin, arsenic

• 🧠 CML: 9 and 22, BCR-ABL, Philadelphia's Pair — t(9;22)

• 🧠 CLL: Five-Twenty-Three (CD5, CD23) — markers

• 🧠 PV: Hot shower Itch, JAK2 — aquagenic pruritus

Rapid-Revision Cards

• Neutropenia grades

  < 1500; moderate 500–1000; severe < 500.

• Leukaemoid reaction

  Neutrophils > 50,000, non-malignant; cancer or infection.

• Acute vs chronic

  Blasts vs more mature cells.

• ALL

  Commonest childhood cancer; peak 2–5 y; TdT+; CNS, testes.

• AML

  MPO+; Auer rods.

• APL

  t(15;17) PML::RARA; tretinoin + arsenic.

• CLL

  CD5, 19, 20, 23; hypogammaglobulinaemia; AIHA.

• Richter syndrome

  CLL → diffuse large B-cell lymphoma.

• CML

  t(9;22) BCR::ABL1; Ph+ > 90%; low LAP; TKI.

• CML progression

  Rising basophils and blasts.

• MDS

  < 20% blasts; 40–60% → AML.

• Del(5q) MDS

  Severe anaemia + thrombocytosis.

• Polycythaemia vera

  JAK2; aquagenic pruritus; phlebotomy, aspirin.

• Essential thrombocythaemia

  JAK2 V617F ~50%.

• Myelofibrosis

  Teardrop cells; splenic EMH.

Sources

Facts in this article were checked against these documents.

• MSD Manual Professional: Overview of Leukemia; Acute Lymphoblastic Leukemia; Acute Myeloid Leukemia; Chronic Lymphocytic Leukemia; Chronic Myeloid Leukemia; Myelodysplastic Syndromes; Neutropenia; Polycythemia Vera; Essential Thrombocythemia; Primary Myelofibrosis — Merck & Co. (MSD Manuals), reviewed 2025–2026 (link)

• Competency Based Undergraduate Curriculum, Pathology (PA 18) — National Medical Commission, 2024

Test Yourself: Practice Questions

Twenty-five questions in NEET PG style, most of them clinical vignettes.

Practice Questions (NEET PG pattern)

Original questions written in the style of the exam: +4 for a correct answer, −1 for a wrong one. Every answer was checked against the sources listed above. NEET PG papers are not published by NBEMS, so these are not past-paper questions.

Q1. A 4-year-old has fever, pallor, bruising and bone pain; the smear shows pancytopenia with blasts that are TdT positive. The diagnosis is

• (a) acute myeloid leukaemia

• (b) acute lymphoblastic leukaemia

• (c) aplastic anaemia

• (d) CLL

Q2. The commonest cancer in children is

• (a) retinoblastoma

• (b) acute lymphoblastic leukaemia

• (c) Wilms tumour

• (d) neuroblastoma

Q3. Without prophylaxis, a leukaemia that commonly involves the central nervous system is

• (a) CLL

• (b) ALL

• (c) CML

• (d) AML

Q4. A 50-year-old has blasts with linear azurophilic cytoplasmic inclusions that stain for myeloperoxidase. The inclusions are

• (a) Heinz bodies

• (b) Dohle bodies

• (c) Howell-Jolly bodies

• (d) Auer rods (AML)

Q5. Acute promyelocytic leukaemia carries the translocation

• (a) t(11;14)

• (b) t(15;17) PML::RARA

• (c) t(8;14)

• (d) t(9;22) BCR::ABL1

Q6. APL is now commonly treated without conventional chemotherapy using

• (a) hydroxyurea alone

• (b) rituximab

• (c) imatinib

• (d) tretinoin and arsenic trioxide

Q7. A 70-year-old man has painless lymphadenopathy and a lymphocyte count of 40,000/µL; cells express CD5, CD19, CD20 and CD23. The diagnosis is

• (a) chronic lymphocytic leukaemia

• (b) CML

• (c) infectious mononucleosis

• (d) ALL

Q8. A CLL patient has recurrent bacterial infections. A likely cause is

• (a) neutrophilia

• (b) iron overload

• (c) hypogammaglobulinaemia (in up to two-thirds)

• (d) hypersplenism only

Q9. A man with long-standing CLL suddenly develops rapidly enlarging nodes and fever; biopsy shows diffuse large B-cell lymphoma. This is

• (a) Hodgkin lymphoma

• (b) blast crisis of CML

• (c) leukaemoid reaction

• (d) Richter syndrome

Q10. A 45-year-old has massive splenomegaly, a very high white count with the whole myeloid series, and low leukocyte alkaline phosphatase. The key test is

• (a) Philadelphia chromosome / BCR::ABL1

• (b) JAK2 alone

• (c) TdT staining

• (d) flow cytometry for CD55

Q11. In CML, the Philadelphia chromosome arises from

• (a) t(8;14)

• (b) t(9;22), fusing ABL from chromosome 9 to BCR on chromosome 22

• (c) t(15;17)

• (d) deletion of 5q

Q12. First-line treatment of chronic-phase CML is

• (a) a tyrosine kinase inhibitor

• (b) rituximab

• (c) splenectomy

• (d) tretinoin

Q13. In a patient with CML, increasing blood basophils and blasts suggest

• (a) infection only

• (b) progression to accelerated phase

• (c) response to treatment

• (d) iron deficiency

Q14. A man with severe pneumonia has neutrophils of 60,000/µL; no blasts or Philadelphia chromosome. This is

• (a) AML

• (b) a leukaemoid reaction

• (c) CML

• (d) CLL

Q15. A patient on chemotherapy has an absolute neutrophil count of 300/µL. The neutropenia is

• (a) moderate

• (b) normal

• (c) mild

• (d) severe (< 500), with risk of infection from own gut and mouth flora

Q16. MSD gives the usual lower limit of a normal absolute neutrophil count in adults (somewhat lower in some ethnic groups) as about

• (a) 500/µL

• (b) 1500/µL

• (c) 4000/µL

• (d) 100/µL

Q17. An elderly patient has cytopenias, a dysplastic marrow and 12% blasts. The diagnosis is

• (a) AML

• (b) aplastic anaemia

• (c) myelodysplastic syndrome (blasts < 20%)

• (d) CLL

Q18. An older woman has severe anaemia with a raised platelet count; marrow cytogenetics shows deletion of the long arm of chromosome 5. This is

• (a) CML

• (b) essential thrombocythaemia

• (c) MDS with isolated del(5q)

• (d) iron deficiency

Q19. A man has a raised haemoglobin and itching after hot showers. The test to order is

• (a) TdT

• (b) JAK2 mutation

• (c) BCR::ABL1

• (d) CD5

Q20. Treatment of polycythaemia vera includes

• (a) iron supplements

• (b) splenectomy first

• (c) erythropoietin

• (d) phlebotomy and low-dose aspirin (ruxolitinib or interferon if needed)

Q21. In essential thrombocythaemia, the JAK2 V617F mutation is found in about

• (a) 90%

• (b) 5%

• (c) 50% of patients

• (d) 100%

Q22. A man with splenomegaly and marrow fibrosis has teardrop and nucleated red cells. The diagnosis is

• (a) ALL

• (b) primary myelofibrosis

• (c) CML

• (d) iron deficiency

Q23. Myeloperoxidase staining is positive in

• (a) red cells

• (b) lymphoid cells

• (c) myeloid cells (AML)

• (d) plasma cells

Q24. Compared with acute leukaemias, chronic leukaemias have

• (a) no spleen involvement

• (b) more mature cells

• (c) more blasts

• (d) always pancytopenia

Q25. A patient with a very high white count and splenomegaly has a low leukocyte alkaline phosphatase (LAP) score. This favours

• (a) primary myelofibrosis

• (b) polycythaemia vera

• (c) a reaction to infection

• (d) chronic myeloid leukaemia

Active Recall

From memory: define neutropenia grades and a leukaemoid reaction; contrast ALL, AML, CLL and CML (cells, markers, counts, nodes, spleen, genetics, treatment); and describe MDS, polycythaemia vera, essential thrombocythaemia and myelofibrosis.