Bone Marrow: WBC and Platelet Progenitors ( inherited disorders and infections

Question 1

State what evaluations are done at low and high power when examining a bone marrow specimen.

Answer 1

At low power (20X) MT’s examine the ratio of marrow to fat, which is normally 1:1.

(>4:1 is considered hypercellular and 1:4 is considered hypocellular)

At high power (100X) MT’s examine the myeloid:erythroid ratio

•Other cells unique to marrow will be present

–Macrophages

–Osteoblasts (build bone)

–Osteoclasts (catabolize bone)

Question 2

Is this abnormal or normal marrow?

Answer 2

Normal Marrow:

• Erythroblasts 20%
• Myeloblasts 2%
• Promyelocytes 2%
• Neutrophils 57%
• Monocytes 2%
• Eosinophils 3%
• Basophils 1%
• Lymphocytes 10-12%
• Plasma cells 2%

Question 3

How does infection affect the Bone Marrow M:E ratio? What is going on exactly?

Answer 3

During Infection the M:E ratio increasea to 5:1 and the BM displays hyperplasia. (proliferation of cells beyond what is normally seen)

Lymphs and neutrophils are expanding their population in the circulation.

Question 4

How does Dysplasia affect the Bone Marrow M:E ratio? What is going on exactly?

Answer 4

When the bone marrow is dysplastic there is a greater than normal amount of precursor cells and their morphology is abnormal. (5-20% blasts)

(can be caused by sideroblastic and refractory anemia)

–

Question 5

Define Leukemia? Lymphoma?

Answer 5

Leukemia: Cancers of the blood. It begins in the BM, and the abnormal cells can spread from there into the bloodstream and other areas of the body.

_{–Myeloid, lymphoid, erythroid, megakaryocytic}

•Lymphoma: Cancers of the lymphatic system (_{a complex network<br></br>of tubes (lymphatic vessels), glands (lymph nodes) and other organs including the spleen<br></br>and thymus gland. Lymph nodes are found in the neck, armpits, groin, chest, abdomen and<br></br>pelvis.)}

When your lymphocytes are out of control, abnormal lymphocytes build up in lymph nodes, BM, spleen and other areas of the body.

_{–Bone marrow may or may not be abnormal}

_{–Hairy cell – dry tap because of myelofibrotic cells}

Question 6

Decribe this photo.

Answer 6

Myelofibrosis

Question 7

Describe photo.

Answer 7

Hyperplasia

Question 8

What is hypoplasia?

Causes?

Answer 8

Underdevelopment or incomplete development of a tissue or organ. Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells.

Causes:

• Old age
• BM taken from the cortex, rather than the medulla
• Aplastic anemia
• Reticular fibrosis

Question 9

Difference between toti-, pluri-, and multipotent stem cells?

Answer 9

Totipotent cells can form all the cell types in a body, plus the extraembryonic, or placental, cells. Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent. Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent. Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.

Question 10

Describe blood cell lineages. (stem cell———>differentiated)

Answer 10

Question 11

Answer 11

•Myeloblast

–Size: 15-20 microns

–N:C ratio – 7:1 - 4:1

–Cell characteristics: round nucleus with delicate disbursed chromatin, 2-3 nucleoli, pale blue cytoplasm with varying amounts of granules

Question 12

Answer 12

Promyelocyte

Size: 18-25 microns

N:C ratio – 2:1-5:1

Cell characteristics: round or oval nucleus with 2-3 nucleoli, and blue cytoplasm with few to many dark blue granules (primary granules)

Question 13

Answer 13

•Myelocyte

–Size:12-18 microns

–N:C ratio – 3:1-3:2

–Cell characteristics: Coarser chromatin with few to no nucleoli – cytoplasm is pinkish blue with primary and secondary (specific) granules present

Question 14

Answer 14

Metamyelocyte

Cell characteristics: Kidney shaped or indented nucleus with course chromatin and no nucleoli – pink-blue cytoplasm with pinkish to reddish-blue granules

Question 15

Answer 15

•Neutrophils

–Size: 10-16 microns

–N:C ratio 1:3-1:5

–Cell characteristics: dark purple nucleus with heavily clumped chromatin – pink cytoplasm with pink to violet granules

Question 17

Answer 17

Eosinophils

Size: 10-16 microns

N:C ratio 1:3 – 1:5

Cell characteristics as above with red orange granules

Question 18

Answer 18

Basophils

Size: 10-16 microns

N:C ratio 1:3 – 1:5

Cell characteristics as above with few dark blue-black granules

Question 19

Answer 19

•Monoblast

–Size: 14-20 microns

–N:C ratio – 3:1 – 1:1

–Cell characteristics – round to oval nucleus with fine distinct chromatin and 1-5 nucleoli – cytoplasm is blue-grey with no granules

Question 20

Answer 20

Promonocyte

Size: - 14-20

N:C ratio – 2:1 – 1:1

Cell characteristics – Oval or indented nucleus with fine reticular chromatin and 1-3 nucleoli – cytoplasm is glue-grey, finely granular (ground glass) and may have occasional vacuoles

Question 21

Answer 21

•Monocytes

–Size: 14-21 microns

–N:C ratio 1:1

–Cell characteristics: Horseshoe shaped or indented nucleus with folding, fine delicate linear strands of chromatin – many fine dust like granules, occasional vacuole and blunt pseudopods

Question 22

How can you visually differentiate between monocytes and lymphocytes?

Answer 22

•Different from lymphs because

–Cytoplasm is more grey

–Nucleus is folded

–Cytoplasm does not “bend” around RBCs

Question 23

Answer 23

•Megakaryoblast

–Size: 20-50 microns

–N:C ratio – 5:1 – 3:1

–Cell characteristics – round or oval nucleus with fine distinct strands to dense chromatin with distinct nucleoli – cytoplasm is moderate to dark blue with some to no fine granules

•Promegakaryocyte

–Size: 20-80 microns

–N:C ratio – 1:1

–Cell characteristics – Irregular indented nucleus with 2-4 lobes

Question 24

Answer 24

•Megakaryocytes

–Size: 40-100 microns

–N:C ratio – 1:1 – 1:12

–Cell characteristics – Multi-lobed nucleus with coarse linear chromatin and no nucleoli – cytoplasm is pinkish-blue with pinkish blue granules

•Platelets / thrombocytes

–Size:1-4 microns

–Cell characteristics – small granular anuclear cells

Question 25

Answer 25

•Lymphoblast –Size: 10-22 microns –N:C ratio – 7:1-4:1 –Cell characteristics – Round or oval central or eccentric nucleus with fine lacy chromatin and 1-2 prominent nucleoli – cytoplasm is dark blue and smooth, without granules

Question 26

Answer 26

•Prolymphocyte –Size: 10-15 microns –N:C ratio – 3:1-4:1 –Cell characteristics – round centrally placed nucleus that is reddish purple with coarse clumped chromatin (ginger snap) – abundant light to medium blue cytoplasm

Question 27

Answer 27

•T-cells / B-cells –Size: 7-15 microns –N:C ratio – 3:1 ratio –Cell characteristics – round or slightly indented nucleus with course clumped chromatin and no visible nucleoli - sky blue to deep blue cytoplasm

Question 28

Answer 28

Plasma Cells Size: 9-20 microns Cell characteristics – Dark purple nucleus is ovoid and eccentrically placed with no nucleoli – cytoplasm is abundant and deep blue with clear area near the nucleus

Question 29

Cytochemical Stains used to evaluate bone marrow.

Answer 29

**^{•Acid Phosphatase}** ^{– focal staining in T-cells} **^{•Tartrate Resistant Acid Phosphatase (TRAP)}** ^{–positive in hairy cell leukemia because AP is not inhibited by tartrate} **^{•Alkaline phosphatase}** ^{–present in neutrophils} **^{•Leukocyte alkaline phosphatase score}** ^{– used to differentiate leukemoid reaction (high score) from leukemia (low score)} **^•Esterases** ^{–Specific esterase (chloroacetate) •Neutrophils and mast cells –Non-specific esterase (alpha-naphthyl acetate) •Monocytes •Megakaryocytes •Plasma cells} **^{•Peroxidase}** ^{–Variable depending on the maturity of the cell –Neutrophil granules stain black –Eos stain redish brown} **^{•Sudan Black B}** ^{–Positive in granulocytes, monocytes –Negative in lymphocytes} **^{•Iron Stain}** ^{–Look for blue green granules –Seen in erythroid precursors –Ringed sideroblasts} **^{•TdT – terminal deoxy nucleotidyl transferase}** ^{–Strongly positive in lymphocytes} **^{•PAS – carbohydrate stain}** ^{–Distinguishes Gaucher’s from Neiman Pick –Erythroid leukemia –80% of all ALL are positive}

Question 30

Why are some sytochemical stains no longer used or necessary?

Answer 30

* Some of the stains are no longer necessary due to the advent of f**low cytometry**, which identifies cells by their surface markers called cluster designations. (immunophenotyping) * _{Cell surface markers are acquired and lost as a cell matures, making for a more specific identification than a staining technique}

Question 31

What changes occur among precursoe cells in the bone marrow due to megaloblastic anemia?

Answer 31

* Hypersegmentation * Discontinuity of the nuclear and cytoplasmic development * Giant megakaryocytes

Question 32

Answer 32

Toxic Granulation ## Footnote * Associated with infection or activation of neutrophils * Dark purple granules occur in the cytoplasm

Question 33

Answer 33

Dohle Bodies ## Footnote * Rough ER remnants * Associated with stress, infection, neoplasm and exposure to cytotoxic agents

Question 34

Inherited wbc disorder?

Answer 34

Pelger-Huet Anomaly * Common disorder – 1/6,000 * Morphology – bilobed or unlobed neutrophils – can be interpreted as immature cells * No symptoms * Cells function normally * No treatment necessary

Question 35

Inherited wbc disorder?

Answer 35

Alder-Reilly Anomaly * Recessive with variable phenotypes * Morphology –Lipids in the cytoplasm of most cells –“Alder-Reilly Bodies” –Looks like toxic granulation •Symptoms/Prognosis –Cell function is normal –Mucopolysaccharidosis associated with this – Hurler’s or Hunter’s disease

Question 36

Inherited wbc disorder?

Answer 36

Chediak-Higashi Syndrome ## Footnote •Morphology –Giant fused granules in neutrophils and lymphs •Symptoms/Prognosis –Cells engulf but do not kill microbes –Death in early childhood from pyrogenic infections –Skin hypopigmentation –Silvery hair –Photophobia –Lymphadenopathy, hepatosplenomegaly

Question 37

Inherited wbc disorder?

Answer 37

May-Hegglin Anomaly * Autosomal Dominant * Morphology –Blue Dohle-like inclusions in all granulocytes –Giant platelets •Symptoms/Prognosis –Cells function normally –Variable thrombocytopenia may lead to bleeding

Question 38

Inherited wbc disorder? Morphology –Normal Wright’s stain –NBT (nitroblue tetrazolium) negative •Symptoms/Prognosis –No oxidative burst – cells cannot kill bacteria •Treatment –Prophylactic antibiotics –Aggressive treatment of infections

Answer 38

Chronic Granulomatous Disease •

Question 39

Inherited wbc disorder?

Answer 39

Gaucher's Disease •Morphology –Macrophages have swirly or crumpled tissue paper cytoplasm –Accumulate glucocerebroside •Symptoms/Prognosis –Spleen and liver are greatly enlarged –Increased serum acid phosphatase –Prognosis varies depending on the type of disease inherited •Treatment –Bone marrow transplant Supplementation with enzyme

Question 40

Inherited wbc disorder?

Answer 40

Niemann-Pick Disease * Autosomal recessive * Morphology –Macrophages have foamy cytoplasm due to an accumulation of sphingomyelinase •Symptoms/Prognosis –Fatal by three years of age •Treatment - none