Question 1

Which of the following would stain most strongly for myeloperoxidase?&#10;A) Lymphoblasts&#10;B) Auer rods&#10;C) Monocytes&#10;D) Normal myeloblasts

Accepted Answer

Auer rods, which are found in myeloid blasts (particularly in acute myeloid leukemia), are strongly positive for myeloperoxidase staining. This enzyme is abundant in cells of the myeloid lineage, especially in those involved in the production of reactive oxygen species used in the microbial killing.

Question 2

A patient has a leukocyte alkaline phosphatase score of 9. The positive control is 5. Select the correct interpretation.&#10;A) Chronic myelogenous leukemia&#10;B) Acute lymphocytic leukemia&#10;C) Polycythemia vera&#10;D) Test must be repeated

Accepted Answer

Test must be repeated

Question 3

The bone marrow of a patient with acute leukemia is stained with the periodic acid-Schiff (PAS) stain. When this stain is evaluated, segmented neutrophils show diffuse pink staining. Select the correct interpretation.

A) The patient has acute lymphoblastic leukemia.
B) The patient has acute myeloid leukemia.
C) The stain did not work.
D) No conclusion can be reached; blast cells must be examined.

Accepted Answer

The PAS stain highlights glycogen, and while it can show certain characteristics in cells, the diagnosis of specific types of leukemia, such as acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML), relies on the appearance and characteristics of blast cells, not segmented neutrophils. Therefore, without examining blast cells, no definitive conclusion about the type of leukemia can be made.

Question 4

A myeloperoxidase stain is performed on peripheral blood cells of a patient with acute leukemia and 85% blasts; the patient has an occasional mature neutrophil. When the stained slide is evaluated, the blasts are all negative but the mature neutrophils are strongly positive. What is the significance of this finding?

A) The stain worked (internal positive control).
B) Nothing can be determined until a positive control is also examined.
C) Nothing can be determined because mature neutrophils are always positive.
D) Nothing can be determined because only examination of the blasts is useful.

Accepted Answer

The myeloperoxidase stain is a cytochemical test used to differentiate types of leukemia by staining myeloid cells. The fact that the mature neutrophils are strongly positive confirms that the stain worked properly, acting as an internal positive control. This indicates that the procedure was performed correctly, and the negative result in the blasts is meaningful, suggesting they are likely not of myeloid origin.

Question 5

Sudan black is used to distinguish which types of leukemia?&#10;A) Acute myeloid leukemia from acute lymphoblastic leukemia&#10;B) Acute myeloid leukemia from chronic myelogenous leukemia&#10;C) Acute myeloid leukemia from acute promyelocytic leukemia&#10;D) Acute promyelocytic leukemia from acute myelomonocytic leukemia

Accepted Answer

Sudan black is a stain used in diagnosing leukemia types, particularly effective in distinguishing acute myeloid leukemia (AML) from acute lymphoblastic leukemia (ALL) by staining myeloid granules, which are present in AML but not in ALL.

Question 6

Tartrate-resistant acid phosphatase is strongly positive in which of the following cells?&#10;A) Myeloblasts&#10;B) Hairy cells&#10;C) Granulocytes&#10;D) Lymphocytes

Accepted Answer

Tartrate-resistant acid phosphatase (TRAP) staining is a characteristic marker of hairy cell leukemia, a rare type of leukemia in which the cancerous cells are B lymphocytes (a type of white blood cell). This staining helps differentiate hairy cell leukemia from other types of leukemia and lymphoma.

Question 7

What cells may demonstrate a coarse block pattern of activity with the PAS stain?&#10;A) Normal lymphocytes&#10;B) mature neutrophils&#10;C) Normal erythroid precursors&#10;D) Malignant lymphoblasts

Accepted Answer

Malignant lymphoblasts can demonstrate a coarse block pattern of activity with the PAS stain due to the accumulation of glycogen and other carbohydrates within the cytoplasm. This is a characteristic feature of lymphoblasts in acute lymphoblastic leukemia (ALL). Normal lymphocytes, mature neutrophils, and normal erythroid precursors are not expected to exhibit this pattern of activity with PAS stain.

Question 8

Cytochemical procedures stain what cellular elements?&#10;A) Enzymes&#10;B) Lipids&#10;C) Glycogen&#10;D) All of the above

Accepted Answer

Cytochemical procedures stain various cellular elements such as enzymes, lipids, and glycogen. Therefore, the best choice is D - all of the above.

Question 9

A patient has a white blood count of 35 *10⁹/L with a left shift. The leukocyte alkaline phosphatase stain is 220. Which of the following is most likely? A) Severe bacterial infection B) Chronic myelogenous leukemia C) Paroxysmal nocturnal hemoglobinuria D) Values normal

Accepted Answer

A white blood count of 35 with a left shift and a high leukocyte alkaline phosphatase stain is most likely indicative of a severe bacterial infection. Chronic myelogenous leukemia would have a higher leukocyte alkaline phosphatase score, and paroxysmal nocturnal hemoglobinuria would not typically present with a left shift in the white blood count. The option of "values normal" is incorrect given the elevated white blood count and left shift.

Question 10

A patient has a very high white blood count with many blasts in the blood and bone marrow. Esterase stains using both naphthol AS-D chloroacetate and $\alpha$ -naphthyl acetate esterase as substrates are both positive. What condition is likely?

A) Chronic myelogenous leukemia
B) Acute lymphoblastic leukemia
C) Acute myelomonocytic leukemia
D) Hairy cell leukemia

Accepted Answer

The high WBC count with many blasts and positive esterase stains (both naphthol AS-D chloroacetate and F1F1F1S1​αF1F1F10-naphthyl acetate esterase) suggest a diagnosis of acute myelomonocytic leukemia. Chronic myelogenous leukemia (A) would have a Philadelphia chromosome and the presence of the BCR-ABL fusion protein. Acute lymphoblastic leukemia (B) would have a different set of markers on flow cytometry and would not stain positive for esterase. Hairy cell leukemia (D) would have tartrate-resistant acid phosphatase (TRAP) staining.

Deck 30: Cytochemistry