Hematopathology

Question 1

Differential for non-megaloblastic macrocytosis

Answer 1

• Liver disease
• Reticulocytosis (due to retics)
• Myelodysplastic syndrome

Question 2

What does a finding of rouleaux on hematopathology represent?

Answer 2

High concentration of protein, usually fibrinogen or immunoglobulins

However! There is always rouleaux on the location a drop of blood is placed on the slide initially. So, make sure you look at the whole slide before calling rouleaux.

Question 3

Agglutination

Answer 3

Question 4

Stomatocytes

Answer 4

Question 5

Acanthocytes

Answer 5

Question 6

Echinocytes

Answer 6

Question 7

When you see dacryocytes, you need to check. . .

Answer 7

. . . if they are all facing the same direction

If so, it is likely an artifact

Question 8

Blister cells

Answer 8

Question 9

Hemoglobin C disease

Answer 9

Question 10

Hb SC disease

Answer 10

Question 11

Howell-Jolly bodies

Answer 11

Question 12

Pappenheimer bodies

Answer 12

Question 13

Basophilic stippling

Answer 13

Question 14

Heinz bodies

Answer 14

Note: These are usually visualized with a methylene blue stain

Question 15

Cabot ring

Answer 15

Question 16

Ways to differentiate babesia from malaria

Answer 16

1. Maltese cross formation is always babesia
2. Babesia will have mostly rings and rarely maltese crosses, but no other intracellular forms – malaria can take a few shapes
3. Babesia may live extracellularly, so you may catch some parasites outside red cells. Malaria is obligate intracellular.
4. Travel history! Babesia is common in the US and some parts of Europe. Malaria is across tropical areas, but especially tropical Africa and Asia

Question 17

Active CD8+ T cells

Answer 17

Question 18

Toxic granulation

Answer 18

Question 19

Dohle bodies

Answer 19

Question 20

Alder-Reilly anomaly

Answer 20

Question 21

Pelger Huet anomaly

Answer 21

• “Dumbell neutrophils”
• Acquired form is “pseudo-Pelger-Huet”, which may be in association with myelodysplasia

Question 22

Chediak Higashi syndrome

Answer 22

Visualization of these cells on the smear is diagnostic of the condition

Question 23

Histoplasmosis

Answer 23

Question 24

Anaplasmosis / Ehrlichosis

Answer 24

Note: Usually only present during the first week of infection

Question 25

Large platelet syndromes

Answer 25

Question 26

Platelet clumping and satelliting

Answer 26

Question 27

Gelatinous transformation

Answer 27

Question 28

Parvovirus B19 in bone marrow

Answer 28

Question 29

Hemophagocytosis

Answer 29

Question 30

Macrophages in lipid storage diseases

Answer 30

Question 31

Lymph node medulla

Answer 31

Cords: Contain T cells, plasma cells, and macrophages Sinuses: Contiguous with the efferent lymphatics. Contain a large number of monocytes which filter incoming material.

Question 32

Structure of a secondary follicle

Answer 32

Note: Occasionally there is a marginal zone between the mantle and germinal center. This is most common in the spleen. This area houses mature lymphocytes with moderate amounts of pale cytoplasm, including marginal zone B cells.

Question 33

Differentiating cells by nuclei in a germinal center

Answer 33

Question 34

Centroblast vs centrocyte

Answer 34

* B cells within a germinal center * Centroblast: The replicating B cells with euchromatin, contained within the dark zone * Centrocyte: The progeny of the replicating B cells, which migrate to the light zone of the germinal center following division. Here, they interact with DCs and T cells in the light zone to determine if their affinity is sufficient to migrate back to the dark zone and become centroblasts or to become memory B cells.

Question 35

Germinal B cell markers

Answer 35

* Bcl6 * CD10

Question 36

Follicular DC markers

Answer 36

* CD23 * CD35 * CD21 * CD11b/CD18

Question 37

Follicular helper T cell markers

Answer 37

* CD4 * CD57 * PD-1 * Bcl6

Question 38

Proliferation marker for germinal centers

Answer 38

Ki67

Question 39

BCL2 in germinal centers

Answer 39

BCL2 is an anti-apoptotic protein found in mature lymphocytes. It is not present in a benign secondary germinal centers except very scarcely. Mature lymphocytes in the mantle zone will be BCL2 positive. However, primary germinal centers *will* express BCL2, as they do not contain any replicating B cells. As such, **malignant follicles may have BCL2 expression AND be positive for B cell markers like CD20, CD10**

Question 40

Follicular pattern of lymphoid hyperplasia

Answer 40

* Increase in # and size of LN follicles. Germinal centers may be large and irregularly shaped, but maintain features of benign germinal centers (polarization into light and dark zones, preserved mantle zones, tingible body macrophages. * Occurs with: * Idiopathic Follicular hyperplasia * Syphilis * HIV lymphadenopathy * Castlemann disease * Progressive transformation of germinal centers

Question 41

Sinus pattern of lymphoid hyperlasia

Question 42

Tingible body macrophages

Question 43

Partacortical hyperplasia

Answer 43

* Expansion of the paracortical space between follicles. Heterogeneous population of small lymphocytes, larger immunoblasts, and immunoblasts is present. * Can be seen in: * **EBV lymphadenitis** * **HSV lymphadenitis** * **Granulomatous lymphadenitis** * **Dermatopathic lymphadenopathy** * **Drug reaction** * **Toxoplasmosis**

Question 44

CD10

Answer 44

* Function: Cell membrane metalloprinteinase * In T cells and B cells: Marker of a follicular cell. Can help identify TfH and follicular B cells * Mature neutrophils (but not immature)

Question 45

Progressive transformation of germinal centers

Answer 45

Question 46

Follicular lysis

Answer 46

Question 47

Paracortical hyperplasia

Answer 47

Question 48

Sinus histiocytosis

Answer 48

Question 49

Bartonella hensleae lymphadenitis OR lymphogranulosum venereum (L1-3 serotype chlamydia) lymphadenitis

Answer 49

Question 50

Bacillary angioatosis

Answer 50

Question 51

Syphilis lymphadenitis

Answer 51

Question 52

Toxoplasma lymphadenitis

Answer 52

Question 53

Epithelioid histiocytes

Answer 53

Look like islands of epithelial tissue in a lymph node, marrow, or stroma, but then when you look closer they are macrophages

Question 54

Progression of HIV lymphadenitis

Answer 54

Question 55

Birbeck granules

Answer 55

* Tennis-racket-shaped granules found only in Langerhans cells * Visualized by electron microscopy

Question 56

Secondary HLH

Answer 56

* Commonly associated with hematologic malignancies, in particular **NK/T cell neoplasms.** It is only rarely reported in association with other cancers. * **Acute HIV infection** has been implicated in the development of HLH, but typically **in the setting of other acute infections** or **HIV associated lymphomas**, especially **EBV related lymphoproliferative processes** * May be seen in **up to 60% of patients with sepsis**

Question 57

Virus most associated with hemophagocytic lymphohistiocytosis?

Answer 57

* Epstien-Barr virus

Question 58

Reed Sternberg (classical and non-classical) immunophenotype

Answer 58

Question 59

Richter syndrome / Richter transformation

Answer 59

A transformation of B cell chronic lymphocytic leukemia (CLL) or hairy cell leukemia into a fast-growing diffuse large B cell lymphoma

Question 60

Oncocytic morphology

Answer 60

An oncocyte is an **epithelial cell** characterized by an **excessive number of mitochondria**, resulting in an **abundant eosinophilic, granular cytoplasm**

Question 61

CLL hereditary risk

Answer 61

VERY strong hereditary prevalence of CLL

Question 62

Why is it not uncommon to see minor thrombocytosis in anemia?

Answer 62

EPO has some activity at the TPO receptor as well