A 42 year old man was referred with a 2 week history of fever, weakness, and bleeding gums. Peripheral smear showed pancytopenia. The bone marrow examination revealed 26% blasts, frequently exhibiting Auer rods, and mature myeloid cells. An occasional neutrophil with the Pelger-Huet anomaly was also noted. Which of the following cytochemical stains is most likely to be positive?

Question

Image below highlights jugular foramen. Which of the following structures do not pass through the marked structure “A”?

Answer 1

This is a case of a marrow with 26 percent blasts, frequent Auer rods, mature myeloid cells, and a Pelger-Huet neutrophil, a picture of a myeloid blast proliferation with dysplastic features. We need the cytochemical stain that these blasts will most likely turn positive on.

Acid phosphatase: This stain is mainly useful for hairy cell leukemia, where it gives a tartrate resistant pattern, and for some T lymphoblastic cases. It is not the classic stain for a myeloblastic marrow with Auer rods.
Nonspecific esterase: This marks monocytic differentiation. There is no monocytic morphology described here, and Auer rods argue against a purely monocytic process, so this stain is unlikely to be the key positive one.
Myeloperoxidase: Auer rods are made from fused, abnormal primary granules, and these granules are rich in myeloperoxidase. Wherever Auer rods are seen, the myeloperoxidase stain is strongly positive, this is one of the most reliable and classic teaching links in hematology.
Toluidine Blue: This stains basophil and mast cell granules through their metachromatic reaction, it has no particular role in a myeloblastic marrow.

Since the marrow shows blasts with Auer rods plus mature myeloid cells, the lineage is myeloid, and Auer rods are a direct clue that the myeloperoxidase stain will be positive.

Let's summarize:

Auer rods are myeloperoxidase rich structures found in myeloid blasts.
Acid phosphatase and nonspecific esterase point to different lineages, hairy cell or T cell, and monocytic, respectively.
Toluidine blue is for basophil and mast cell granules, not myeloblasts.

So the stain most likely to be positive here is myeloperoxidase.

Answer 2

This is a case of a marrow with 26 percent blasts, frequent Auer rods, mature myeloid cells, and a Pelger-Huet neutrophil, a picture of a myeloid blast proliferation with dysplastic features. We need the cytochemical stain that these blasts will most likely turn positive on.

Acid phosphatase: This stain is mainly useful for hairy cell leukemia, where it gives a tartrate resistant pattern, and for some T lymphoblastic cases. It is not the classic stain for a myeloblastic marrow with Auer rods.
Nonspecific esterase: This marks monocytic differentiation. There is no monocytic morphology described here, and Auer rods argue against a purely monocytic process, so this stain is unlikely to be the key positive one.
Myeloperoxidase: Auer rods are made from fused, abnormal primary granules, and these granules are rich in myeloperoxidase. Wherever Auer rods are seen, the myeloperoxidase stain is strongly positive, this is one of the most reliable and classic teaching links in hematology.
Toluidine Blue: This stains basophil and mast cell granules through their metachromatic reaction, it has no particular role in a myeloblastic marrow.

Since the marrow shows blasts with Auer rods plus mature myeloid cells, the lineage is myeloid, and Auer rods are a direct clue that the myeloperoxidase stain will be positive.

Let's summarize:

Auer rods are myeloperoxidase rich structures found in myeloid blasts.
Acid phosphatase and nonspecific esterase point to different lineages, hairy cell or T cell, and monocytic, respectively.
Toluidine blue is for basophil and mast cell granules, not myeloblasts.

So the stain most likely to be positive here is myeloperoxidase.

Show Hint

The Correct Option is C

Solution and Explanation

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