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Flashcards in WBC Pathology 2 Deck (57)
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1
Q

What is leukopenia?

A

Abnormally low WBC count usually resulting from reduced number of neutrophils (neutropenia).

2
Q

What is lymphopenia?

What can cause it? (5)

A

Reduced levels of lymphocytes.

Congenital immunodeficiency disorder
HIV
Malnutrition
Some viral infections
Autoimmune diseases
3
Q

What is the difference between neutropenia and agranulocytosis?

A

Neutropenia is a reduced level of neutrophils. Agranulocytosis is a clinically significant reduction in neutrophils to result in a higher risk for bacterial and fungal infections.

4
Q

Neutropenia can be cause by which 2 processes?

A
  1. Inadequate/ineffective granulopoiesis.

2. Increased destruction/sequestration of neutrophils in the periphery.

5
Q

What is the most common cause of agranulocytosis?

A

Drug toxicity.

6
Q

What clinical diseases are associated with the following causes of neutropenia or agranulocytosis?

Suppression HSCs
Suppression of committed granulocytic precursors
Ineffective hematopoiesis

Immunologically-mediated injury to neutrophils
Splenomegaly
Increased peripheral utilization

A

Suppression HSCs: aplastic anemia and infiltration marrow disorders.
Suppression of committed granulocytic precursors: drug exposure.
Ineffective hematopoiesis: megaloblastic anemias and myelodyplastic syndromes.

Immunologically-mediated injury to neutrophils: idiopathic, SLE, drug exposure.
Splenomegaly: sequestration of neutrophils.
Increased peripheral utilization: overwhelming bacterial, fungal or rickettsial infections.

7
Q

What are the major infectious causes of acute lymphadenitis in the following regions?

Cervical nodes
Inguinal nodes
Mesenteric nodes

A

Cervical: drainage of microbes or products from infections of the teeth or tonsils.

Inguinal: infections in the extremities.

Mesenteric: draining acute appendicitis.

8
Q

What are examples of chronic lymphadenitis?

A

H. Pylori infection stimulating Peyer’s patches.

RA

9
Q

What is the clinical difference between nodes in acute vs. chronic lymphadenitis?

A

Acute nodes are tender, enlarged and reddened.

Chronic nodes tends to be non-tender and develop over time. They are more common in the inguinal and axillary nodes, which drain large areas of the body.

10
Q

In chronic lymphadenitis, which processes lead to follicular hyperplasia? (3)

What part of the immune system is activated?

A

RA
Toxoplasmosis
Early stages of HIV infection

Humoral immune system (B-cells).

11
Q

In chronic lymphadenitis, which processes lead to paracortical hyperplasia?

What part of the immune system is activated?

A

Acute viral infections (mono).

T-cell immunity.

12
Q

What process leads to sinus histiocytosis?

A

A nearby draining malignancy (often breast carcinoma).

13
Q

What is the definition of ‘hemophagocytic lymphohistiocytosis’ (HLH)?

A

A reactive condition marked by cytopenias and signs/symptoms of systemic inflammation related to macrophage activation (aka: macrophage activation syndrome).

14
Q

What is the common feature of all forms of HLH?

What is the downstream effect of this?

A

Systemic activation of macrophages and CD8+ T-cells.

the activated macrophages and CD8+ cells phagocytose progenitor cells in the marrow and the formed elements in peripheral tissues. As they do this, they release their mediators (cytokines, ILs, etc.) which cause a systemic response. This further leads to cytopenias and a “shock-like” syndrome = cytokine storm.

15
Q

What kind of mutations are familial forms of HLH associated with?

A

Many different ones, but they all impact the ability of cytotoxic T-cells and NK cells to form properly or deploy cytotoxic granules.

16
Q

The most common trigger for HLH =

A

Infection, usually EBV.

17
Q

What is the usual presentation of HLH?

What are common lab findings? (6)

What may ensue if left untreated?

A

Acute fever with splenomegaly and hepatomegaly.

Anemia
Thrombocytopenia
Elevated plasma ferritin
Elevated soluble IL-2R
Elevated LFTs and TGs (associated with hepatitis)
Coagulation abnormalities - DIC

Multiorgan failure, shock and death.

18
Q

What are the major categories of disorders associated with splenomegaly? (6)

A

Infection

Congestive states related to portal HTN (liver diseases, HF, etc.)

Lymphohematogenous disorders (lymphoma, myeloma, anemia, etc.)

Immunological diseases (RA, SLE)

Storage diseases (Gaucher, Niemann-Pick disease, Mucopolysaccharidoses)

Miscellaneous disorders (amyloidosis, primary neoplasms/cysts, metastases, etc.)

19
Q

What is the receptor type of malignant daughter lymphoid cells?

A

The receptors will be the same the malignant progenitor cell, meaning they have the same antigen receptor gene configuration and sequence. They will share the same Igs or TCRs.

20
Q

Acute leukemia of childhood is typically…

Acute leukemia of adults is typically…

A

Children - B-cell entity.

Adults - myeloid entity.

21
Q

What is the most common site of primary extranodal lymphoma?
What kind of lymphoma?

What other sites may exist?

A

GI tract; NHLs.

Skin, spleen, BM, thymus, tonsils and adenoids.

22
Q

Which neoplasm is associated with a t(12;21) translocation involving RUNX1 and ETV6?

A

B-cell ALL

23
Q

Which neoplasm is associated with NOTCH1 mutations?

A

T-cell ALL

24
Q

What age is most common for peripheral B-cell neoplasms?

A

Typically adults

25
Q

What are 3 clinical features of Hairy cell leukemias?

A

Hepatosplenomegaly
Pancytopenia
Infections

26
Q

What is the most common leukemia of adults in the western world?

What age/sex is most common?

A

CLL (lymphocyte ct. > 5000 mm).

60 y/o, M>F

27
Q

In which neoplasm are chromosomal translocations rare?

What do they express instead?

A

CLL

They express pan B-cell markers (CD19, CD20, CD23 and CD6).

28
Q

What is the presentation of CLL?

A

Usually begins asymptomatic and non-specific. About half exhibit hepatosplenomegaly and generalized lymphadenopathy.

29
Q

In which neoplasm might “smudge cells” and scattered spherocytes be noted?

A

CLL

30
Q

What is Richter syndrome?

A

The transformation of CLL to diffuse large B-cell lymphoma.

31
Q

What is the most common form of indolent NHL in the US?

A

Follicular lymphoma

32
Q

What genetic changes are seen in follicular lymphoma?

What translocation is common?

A

BCL2 overexpression (it antagonizes apoptosis).

t(14;18)

33
Q

What is seen in peripheral blood, the bone marrow and the spleen in follicular lymphoma?

A

PB: lymphocytosis (10%).

BM: paratrabecular lymphoid aggregates (85%).

Spleen: involvement of the white pulp and portal triads.

34
Q

What is the presentation of follicular lymphoma?

What is the progression/prognosis?

Does histologic transformation occur?

A

Painless, generalized lymphadenopathy.

It follows a waxing/waning course. It is not curable and has a mean survival time of 7-9 years. It is treated with low-dose chemotherapy or immunotherapy.

Histologic transformation to diffuse B-cell lymphoma (most common), or Burkitt lymphoma (less common) if there are translocations involving MYC.

35
Q

What is the most common form of NHL?

What is the most common age/sex?

A

Diffuse large B-cell lymphoma (DLBCL).

M>F; 60 y/o, but can occur in young adults and kids.

36
Q

What molecular changes are seen in DLBCL?

A

BCL6 dysregulation

Small percentage have t(14;18) at BCL2.

37
Q

Which viruses are associated with DLBCL?

A

EBV

KSHV/HHV-8 (primary effusion lymphoma)

38
Q

What is the course of DLBCL?

What sites are often involved? (3)

What site is not usually involved?

A

It is aggressive and rapidly fatal without treatment. It presents as a rapidly-enlarging mass that can arise anywhere.

Waldeyer ring is often involved.
Primary or secondary involvement of the liver and spleen may result in large destructive masses.
Extranodal sites are common.

BM involvement is uncommon.

39
Q

What genetic change is seen in Burkitt lymphoma?

Unlike other tumors of germinal B-cells, Burkitt lymphoma usually does not express what?

A

Translocations of c-MYC on chr. 8.

BCL2 is not expressed (anti-apoptotic protein).

40
Q

What are the 3 subtypes of Burkitt lymphoma?

What pattern is seen on histology?

A

African (endemic)
Sporadic (non-endemic)
HIV patients

“Starry sky”.

41
Q

Which tumor is considered to be the “fastest growing human tumor”?

A

Burkitt lymphoma

42
Q

Who is most likely to get Burkitt lymphoma?

How common is it?

Where does it tend to manifest?

A

Children or young adults.

They make up 30% of childhood NHL.

Most manifest at extranodal sites.

43
Q

What is the average age of diagnosis of HL?

Is it curable?

A

32 y/o, but it is the most commonly diagnosed cancer of teenagers (15-19 y/o).

Yes, it is usually curable and was the first cancer treated with radiation therapy and chemo.

44
Q

Why is staging more useful in HL than NHL?

A

Because HL arises at 1 node or chain of nodes and first spreads to contiguous lymphoid tissues.

45
Q

What is the neoplastic cell in HL?

A

A giant cell of the B-cell lineage known as the Reed-Strenberg cell; it represents wholesale reprogramming of the B-cell genome.

46
Q

What do Reed-Sternberg cells do in the pathogenesis of

What is the genetic makeup of these cells?

How do they effect nearby cells?

A

They release many cytokines, chemomines and other factors which induce accumulation of reactive lymphocytes, macrophages and granulocytes - these make up >90% of the tumor cellularity.

They are aneuploid and have diverse colonial chromosome aberrations.

They undergo “cross-talk” between RS cells and the normal cells (CD30L, bFGF, M-CSF, etc.).

47
Q

What are the 4 classic types of HL?

A

Nodular sclerosis

Mixed cellularity

Lymphocyte-rich

Lymphocyte depletion

48
Q

What is Nodular Sclerosis HL?

What is it associated with?

What sites are involved?

What is the prognosis?

A

It is the most common form of HL.

It uncommonly associated with EBV. Equal gender involvement.

It has a propensity for lower cervical and supraclavicular sites, but especially noted for mediastinal involvement.

Prognosis is great.

49
Q

How is the Mixed Cellularity variant of HL differentiated?

Which patient type is most common?

What are the common symptoms?

What is the prognosis?

A

RS cells and variants are highly abundant; they are also infected with EBV in most cases.

M>F with a biphasic distribution.

Usually there is systemic symptoms (night sweats, weight loss) and advanced tumor stage.

Prognosis is still very good.

50
Q

What is the association with Lymphocyte-rush HL?

What is the prognosis?

A

EBV infection in 40% of cases.

Prognosis is great; uncommon.

51
Q

What is the least common (<5%) form of HL?

Is it associated with EBV?

Which patient populations are most implicated?

What is the prognosis?

A

Lymphocyte depletion HL.

Yes, >90% of the time.

Elderly patients, HIV+ of any age, and in non-industrialized countries.

The outcome is less favorable than others.

52
Q

What is the “non-classic” form of HL? Why is it called this?

What cells tend to be more abundant?

Does it transform?

Is it associated with EBV?

A

Lymphocyte predominance HL; because it has a different immunophenotype than the others.

It has more L and H cell (popcorn cell) involvement than RS cells.

Yes, but only in 3-5% of cases it transforms to a DLBCL-resembling malignancy.

No, it is not associated with EBV!

53
Q

What cells are implicated in Mantle cell lymphoma?

What gene is involved?

What is the progression?

A

Naive B-cells.

Cyclin D1 gene translocations.

It is moderately aggressive.

54
Q

What is marginal zone lymphoma?

What is the progression?

A

It is a tumor of antigen-primed B-cells that arise at sites of chronic immune stimulation and remain localized for long periods of time.

Indolent course.

55
Q

What mutation is associated with Hairy cell leukemia?

What is the progression of it?

A

BRAF serine/threonine kinase mutations in mature B-cells.

Very indolent.

56
Q

What are the geneti/infectious associations with the following Peripheral NK/T-cell lymphomas/leukemias?

Anaplastic large cell lymphoma

Adults T-cell leukemia/lymphoma

Large granular lymphocytic leukemia

Extranodal NK/T-cell lymphoma

A

Anaplastic large cell lymphoma: ALK tyrosine kinase activating mutations.

Adults T-cell leukemia/lymphoma: HTLV-1 infection.

Large granular lymphocytic leukemia: STAT3 and autoimmune disorders.

Extranodal NK/T-cell lymphoma: EBV infection.

57
Q

Activation of which transcription factor is a common event in classical HL?

A

NF-kB