Myelodysplastic syndromes

5 DOH Abu Dhabi (HAAD) lab licensing practice questions on Myelodysplastic syndromes, part of Hematology. The first 5 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium

   A 58-year-old woman who had gastric bypass surgery 6 years ago has anemia and neutropenia. Her marrow shows vacuoles in erythroid and myeloid precursors and ring sideroblasts, and her B12 and folate are normal. Which deficiency can produce this MDS-like picture?

   1. AVitamin E
   2. BZinc
   3. CIron
   4. DCopper

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   Answer: D · Copper

   Copper is needed by enzymes that handle iron and support blood cell maturation, so its lack causes anemia, neutropenia, vacuolated precursors and ring sideroblasts that can be mistaken for MDS. Gastric bypass and a high zinc intake are common causes, because zinc blocks copper absorption. The changes reverse with copper replacement, so serum copper and ceruloplasmin should be checked before an MDS diagnosis. B12 and folate deficiency, alcohol and some drugs are the other common mimics.

   • A: Vitamin E deficiency causes hemolysis in premature babies, not marrow dysplasia.
   • B: Excess zinc, not zinc deficiency, leads to copper deficiency.
   • C: Iron deficiency gives microcytic cells and no ring sideroblasts, which need iron to form.

2. Question 2 · Easy

   Which pairing of blood and marrow findings is typical of a myelodysplastic syndrome (MDS)?

   1. AHigh counts with a packed marrow
   2. BCytopenias with a fatty, empty marrow
   3. CHigh platelets with a fibrotic marrow
   4. DCytopenias with a cellular marrow

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   Answer: D · Cytopenias with a cellular marrow

   MDS are clonal stem cell disorders in which marrow precursors are plentiful but many die before they are released (ineffective hematopoiesis). The marrow is therefore usually normocellular or hypercellular, while the blood shows one or more cytopenias. Most patients are older adults, and macrocytic anemia is the commonest presentation. A small group has hypocellular MDS, which must be told apart from aplastic anemia.

   • A: Raised counts with a packed marrow suggest a myeloproliferative neoplasm.
   • B: Cytopenias with a fatty, empty marrow are the picture of aplastic anemia.
   • C: Raised platelets with marrow fibrosis point to a myeloproliferative neoplasm.

3. Question 3 · Medium

   A 45-year-old with pancytopenia has a markedly hypocellular marrow. Which finding favors hypocellular MDS over aplastic anemia?

   1. AA low reticulocyte count
   2. BNo enlargement of the spleen
   3. CFat making up most of the marrow
   4. DDysplastic micromegakaryocytes

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   Answer: D · Dysplastic micromegakaryocytes

   Both conditions can present with pancytopenia and a hypocellular marrow. In aplastic anemia the remaining cells look normal and megakaryocytes are very scarce, whereas dysplastic megakaryocytes, such as small forms with single round nuclei, point to a clonal myeloid disorder. An abnormal karyotype, such as monosomy 7, or increased blasts also favors MDS. Both the biopsy (for cellularity) and the aspirate (for dysplasia and karyotype) are needed to separate them.

   • A: A low reticulocyte count reflects marrow failure in either disorder.
   • B: The spleen is usually normal in size in both.
   • C: A fatty, hypocellular marrow is shared by both conditions.

4. Question 4 · Easy

   On a Perls (Prussian blue) stain of marrow, a ring sideroblast is an erythroid precursor whose iron granules:

   1. ALie only in macrophages beside the cell
   2. BAre one to four fine scattered granules
   3. CEncircle at least a third of the nucleus
   4. DSit in a red cell that has lost its nucleus

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   Answer: C · Encircle at least a third of the nucleus

   Ring sideroblasts are erythroblasts with iron-loaded mitochondria lined up around the nucleus. The WHO definition is at least five iron granules covering at least one third of the nuclear rim. They show a defect in heme synthesis and are counted as a percentage of all erythroid precursors. Normal sideroblasts have only a few scattered granules, and storage iron is judged in marrow macrophages.

   • A: Iron in macrophages is storage iron, not sideroblastic iron.
   • B: A few scattered granules describe a normal sideroblast.
   • D: Iron granules in a red cell without a nucleus make it a siderocyte.

5. Question 5 · Hard

   A 500-cell marrow differential from a 72-year-old with anemia and neutropenia counts 60 myeloblasts. Dysplasia is present in two cell lines, blood blasts are 3%, and there are no Auer rods or AML-defining genetic changes. Which WHO 5th edition category fits?

   1. AMDS with increased blasts-2
   2. BMDS with increased blasts-1
   3. CAcute myeloid leukemia
   4. DMDS with low blasts

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   Answer: A · MDS with increased blasts-2

   Marrow blasts are 60 ÷ 500 × 100 = 12% of nucleated cells. WHO 5th edition sets MDS with low blasts at under 5% marrow and under 2% blood blasts, MDS-IB1 at 5-9% marrow or 2-4% blood blasts, and MDS-IB2 at 10-19% marrow, 5-19% blood blasts or Auer rods. The higher category reached by either the marrow or the blood applies, so 12% marrow blasts gives MDS-IB2 even though the blood count alone fits IB1. At 20% blasts the diagnosis becomes AML.

   • B: The 3% blood blasts fit IB1, but 12% marrow blasts move the case to IB2.
   • C: AML needs 20% blasts, a figure reached only by dividing by 200 instead of 500.
   • D: Low blasts needs under 5% marrow and under 2% blood blasts.