Hematopathology Flashcards
Differential for non-megaloblastic macrocytosis
- Liver disease
- Reticulocytosis (due to retics)
- Myelodysplastic syndrome
What does a finding of rouleaux on hematopathology represent?
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.
Agglutination
Stomatocytes
Acanthocytes
Echinocytes
When you see dacryocytes, you need to check. . .
. . . if they are all facing the same direction
If so, it is likely an artifact
Blister cells
Hemoglobin C disease
Hb SC disease
Howell-Jolly bodies
Pappenheimer bodies
Basophilic stippling
Heinz bodies
Note: These are usually visualized with a methylene blue stain
Cabot ring
Ways to differentiate babesia from malaria
- Maltese cross formation is always babesia
- Babesia will have mostly rings and rarely maltese crosses, but no other intracellular forms – malaria can take a few shapes
- Babesia may live extracellularly, so you may catch some parasites outside red cells. Malaria is obligate intracellular.
- Travel history! Babesia is common in the US and some parts of Europe. Malaria is across tropical areas, but especially tropical Africa and Asia
Active CD8+ T cells
Toxic granulation
Dohle bodies
Alder-Reilly anomaly
Pelger Huet anomaly
- “Dumbell neutrophils”
- Acquired form is “pseudo-Pelger-Huet”, which may be in association with myelodysplasia
Chediak Higashi syndrome
Visualization of these cells on the smear is diagnostic of the condition
Histoplasmosis
Anaplasmosis / Ehrlichosis
Note: Usually only present during the first week of infection
Large platelet syndromes
Platelet clumping and satelliting
Gelatinous transformation
Parvovirus B19 in bone marrow
Hemophagocytosis
Macrophages in lipid storage diseases
Lymph node medulla
Cords: Contain T cells, plasma cells, and macrophages
Sinuses: Contiguous with the efferent lymphatics. Contain a large number of monocytes which filter incoming material.
Structure of a secondary follicle
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.
Differentiating cells by nuclei in a germinal center
Centroblast vs centrocyte
- 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.
Germinal B cell markers
- Bcl6
- CD10
Follicular DC markers
- CD23
- CD35
- CD21
- CD11b/CD18
Follicular helper T cell markers
- CD4
- CD57
- PD-1
- Bcl6
Proliferation marker for germinal centers
Ki67
BCL2 in germinal centers
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
Follicular pattern of lymphoid hyperplasia
- 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
Sinus pattern of lymphoid hyperlasia
Tingible body macrophages
Partacortical hyperplasia
- 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
CD10
- 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)
Progressive transformation of germinal centers
Follicular lysis
Paracortical hyperplasia
Sinus histiocytosis
Bartonella hensleae lymphadenitis OR lymphogranulosum venereum (L1-3 serotype chlamydia) lymphadenitis
Bacillary angioatosis
Syphilis lymphadenitis
Toxoplasma lymphadenitis
Epithelioid histiocytes
Look like islands of epithelial tissue in a lymph node, marrow, or stroma, but then when you look closer they are macrophages
Progression of HIV lymphadenitis
Birbeck granules
- Tennis-racket-shaped granules found only in Langerhans cells
- Visualized by electron microscopy
Secondary HLH
- 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
Virus most associated with hemophagocytic lymphohistiocytosis?
- Epstien-Barr virus
Reed Sternberg (classical and non-classical) immunophenotype
Richter syndrome / Richter transformation
A transformation of B cell chronic lymphocytic leukemia (CLL) or hairy cell leukemia into a fast-growing diffuse large B cell lymphoma
Oncocytic morphology
An oncocyte is an epithelial cell characterized by an excessive number of mitochondria, resulting in an abundant eosinophilic, granular cytoplasm
CLL hereditary risk
VERY strong hereditary prevalence of CLL
Why is it not uncommon to see minor thrombocytosis in anemia?
EPO has some activity at the TPO receptor as well
