Haem: Lymphoma MDT (Laz) Flashcards

1
Q

Outline the difference in prevalence of Hodgkin’s lymphoma and Non-Hodgkin lymphoma.

A
  • NHL = 80%
  • Hodgkin = 20%
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2
Q

Outline the processes by which immunoglobulins and T cell receptors become capable of identifying a wide variety of antigens.

A
  • The germline VDJ genes undergo recombination in the bone marrow to generate a wide repertoire of specificities.
  • In germinal centres, a second stage of DNA alteration involving isotype switching and somatic hypermutation (point mutations) generates even more diversity.
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3
Q

Which proteins carry out VDJ recombination and somatic hypermutation

A

VDJ recombination: RAG1 and RAG2 combine to form RAG complex

SHM: activation induced cytidine deaminase

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4
Q

What is the main downside of the processes that generate variety in immunoglobulins and TCR during the adaptive immune response?

A

Recombination errors and new point mutations can occur

Lymphocytes are reliant on apoptosis to keep their massive proliferation under control (90% of lymphocytes die in the germinal centre)
* If a mutation turns off apoptosis, it can lead to malignancy or autoimmunity

Rapid proliferation within germinal centres - increased risk of DNA replication errors

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5
Q

Outline how chromosomal translocations in B cells can lead to malignancy.

A
  • Immunoglobulin gene promoters in B cells are highly active because they are designed to produce loads of immunoglobulin
  • If an error occurs and an oncogene is translocated downstream of the promoter, malignant genes can be expressed
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6
Q

List some oncogenes that are implicated in lymphoma/leukaemia.

A
  • Bcl2
  • Bcl6
  • Cyclin D1
  • c-Myc
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7
Q

List some risk factors that contribute to the aetiology of NHL.

A
  • Constant antigenic stimulation
  • Viral infection
  • Loss of T cell function (immunosuppression)
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8
Q

List some examples of how constant antigenic stimulation can lead to lymphoma.

A
  • H. pylori → gastric MALT - marginal zone NHL of the stomach
  • Sjogren syndrome → marginal zone NHL of the parotid
  • Coeliac disease → small bowel T cell lymphoma, enteropathy-associated T cell NHL
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9
Q

Give an example of how viral infections that can lead to lymphoma.

A

Direct viral integration: HTLV1

  • HTLV1 infects T cells by vertical transmission
  • May cause adult T cell leukaemia/lymphoma (very aggressive)
  • Caused by viral genome integrating into T cell genome and driving proliferation
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10
Q

Give an example of how loss of T cell function can lead to lymphoma

A

EBV infection and immunosuppression

  • EBV established latent infection in B cells which is kept in check by cytotoxic T cell (kill EBV antigen-expressing B cells)
  • Loss of T cell function (e.g. HIV, post-transplant immunosuppression) can lead to EBV-driven lymphoma
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11
Q

List some different types of tissues of the lymphoreticular system.

A
  • Generative tissue: bone marrow and thymus (generates or matures lymphoid cells)
  • Reactive tissue: lymph nodes and spleen (development of immune reaction)
  • Acquired tissue: extra-nodal lymphoid tissue (e.g. skin, stomach, lung - responsible for developing a local immune response)
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12
Q

List the different cell types of the lymphoreticular system.

A

Lymphocytes
* B cells
* T cells

Accessory cells
* Antigen-presenting cells
* Macrophages
* Connective tissue cells

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13
Q

Describe the normal histological appearance of a lymph node.

A

Round areas full of B cells (B cell follicles)
* Mantle zone - a crescent-shaped region where naïve unstimulated B cells are found
* Germinal centre - where naïve B cells will eventually migrate, and mature B cells will end up in the medulla.
* Antigen presenting cells present antigens to B cells in germinal centre to activate them

Paracortical T cell zone - surrounds the B cell follicles

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14
Q

Describe the composition of T cell areas in lymph nodes.

A
  • Consists of lots of T cells, antigen-presenting cells and high-endothelial venules
  • This is the site where T cells bind to antigens and are selected/activated
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15
Q

What is the main technique used to identify different types of lymphocyte within a lymph node biopsy?

A

Immunohistochemistry

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16
Q

What are the main markers used for B and T cells?

A

T cell = CD3, CD5

B cell = CD20

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17
Q

Define lymphoma.

A
  • Neoplastic proliferation of lymphoid cells forming discrete tissue masses
  • They arise in and involve lymphoid tissues
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18
Q

Which factors are taken into account when classifying a lymphoma?

A
  • Clinical
  • Histological
  • Immunohistochemical
  • Molecular
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19
Q

Outline the WHO classification of lymphoma.

A

Hodgkin lymphoma

  • Classical
  • Lymphocyte predominant
  • Abnormal B cells

Non-Hodgkin lymphoma

  • B cell (MOST COMMON)
    • Precursor B cell neoplasm
    • Peripheral B cell neoplasm (low and high grade)
  • T cell
    • Precursor T cell neoplasm
    • Peripheral T cell neoplasm
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20
Q

Why is non-Hodgkin lymphoma often disseminated at presentation?

A

Neoplastic lymphoid cells circulate in the blood leading to disseminated disease at presentation

NOTE: lymphoid neoplasms can disrupt normal immune functioning leading to immunodeficiencies

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21
Q

What are the diagnostic tools used by pathologists when investigating lymphoma?

A
  • Cytology (from aspiration)
  • Histology (architecture: nodular, diffuse; cells: small round, small cleaved, large)
  • Immunohistochemistry
  • Loss of normal surface proteins
  • Expression of abnormal proteins (e.g. cyclin D1 an Mantle cell lymphoma)
  • Light chain restriction
  • Molecular tools
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22
Q

Which molecular tools are used when investigating lymphoma?

A
  • FISH - identify chromosomal translocations
  • PCR - identify chromosomal translocations transcripts (e.g. bcr-abl transcript in CML)
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23
Q

Give an example of a chromosomal translocation that is diagnostic of lymphoma.

A

11;14 = Mantle Cell Lymphoma

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24
Q

Give an example of a chromosomal translocation that is prognostic in lymphoma.

A

2;5 = anaplastic large cell lymphoma

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25
Q

List some types of low grade lymphoma.

A
  • Follicular lymphoma
  • Small lymphocytic lymphoma (CLL)
  • Marginal zone lymphoma
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26
Q

Name 3 types of high grade lymphoma.

A
  • Diffuse large B cell lymphoma
  • Burkitt’s lymphoma
  • Mantle cell lymphoma
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27
Q

How does follicular lymphoma typically present?

A

Lymphadenopathy in middle-aged or elderly patients

NOTE: it is usually indolent but can transform into a high-grade lymphoma

28
Q

Describe the histological features of follilcular lymphoma.

A
  • Follicular pattern - the follicles are neoplastic and spread from the node into adjacent tissues
  • Cells have a germinal centre cell origin (positive staining for CD10 and Bcl6)
29
Q

Which molecular feature is associated with follicular lymphoma?

A

14;18 translocation involving Bcl2 gene

30
Q

Describe the typical presentation of small lymphocytic lymphoma.

A

Lymphadenopathy or high blood lymphocyte count in middle-aged or elderly patients

31
Q

Outline the histological features of small lymphocyte lymphoma.

A
  • Small lymphocytes
  • Arise from naïve B cells or post-germinal centre memory B cells
  • Cells are CD5 and CD23 positivie
  • They replace the entire lymph node so that you can no longer identify follicles or T cell areas
32
Q

What is the term used to describe the transformation of small lymphocytic lymphoma into a higher grade lymphoma/leukaemia?

A

Richter transformation

33
Q

What is marginal zone lymphoma?

A
  • Arise mainly in extra-nodal sites (e.g. gut, spleen)
  • Thought to arise due to chronic antigenic stimulation
  • Arise from post-germinal centre memory B cells
  • Low-grade disease can be treated by non-chemotherapeutic methods (e.g. H. pylori eradication)
34
Q

Outline the typical presentation of mantle cell lymphoma.

A
  • Typically affects middle-aged males
  • Affects lymph nodes and the GI tract
  • Often present with disseminated disease

NOTE: median survival = 3-5 years

35
Q

Outline the key histological features of mantle cell lymphoma.

A
  • Located in the mantle zone of the lymph node
  • Arise from pre-germinal centre cells
  • Show aberrant expression of cyclin D1 and CD5
36
Q

Which molecular features are characteristic of mantle cell lymphoma?

A
  • 11;14 translocation
  • Cyclin D1 overexpression
37
Q

Outline the typical presentation of Burkitt’s lymphoma.

A
  • Jaw or abdominal mass in children and young adults
  • Associated with EBV

NOTE: this is very agressive

38
Q

Outline the histological features of Burkitt’s lymphoma.

A
  • Arises from germinal centre cells
  • Starry sky appearance
39
Q

Which molecular feature is associated with Burkitt’s lymphoma.

A
  • c-Myc translocation (8;14, 2;8 or 8;22)
40
Q

Outline the typical presentation of diffuse large B cell lymphoma.

A

Middle-aged and elderly patients with lymphadenopathy

41
Q

Outline the histological features of diffuse large B cell lymphoma.

A
  • Arise from germinal centre or pre-germinal centre B cells
  • Large lymphoid cells
  • Lymph node is effaced so follicles and germinal centres cannot be identified
42
Q

List some prognostic association of diffuse large B cell lymphoma.

A

Good prognosis - germinal centre phenotype

Poor prognosis - p53-positive and high proliferation fraction

43
Q

Outline the typical presentation of T cell lymphomas.

A

Middle-aged and elderly patients with lymphadenopathy

NOTE: these are aggressive

44
Q

Outline some key histological features of T cell lymphomas.

A
  • Large T lymphocytes
  • Associated reactive cell population (especially eosinophils)
45
Q

List some types of T cell lymphoma and their associations.

A
  • Adult T cell leukaemia/lymphoma - HTLV1
  • Enteropathy-associated T cell lymphoma - Coeliac disease
  • Cutaneous T cell lymphoma (mycosis fungoides)
  • Anaplastic large cell lymphoma
46
Q

Outline the typical presentation of anaplastic large cell lymphoma.

A

Children and young adults with lymphadenopathy

NOTE: this is aggressive

47
Q

Outline the key histological features of anaplastic large cell lymphoma.

A
  • Large epithelioid lymphocytes
  • T cell or null phenotype (anaplastic)
48
Q

Which molecular features are associated with anaplastic large cell lymphoma?

A
  • 2;5 translocation
  • Alk-1 protein expression - BETTER prognosis
49
Q

List some key differences between Hodgkin and Non-Hodgkin Lymphoma.

A
  • Hodgkin is more localised (usually one nodal site)
  • Hodgkin spreads contiguously to adjacent to adjacent lymph nodes

NOTE: NHL tends to involve multiple lymph node sites and spread discontinuously

50
Q

Outline the typical presentation of classical Hodgkin lymphoma.

A
  • Young and middle-aged patients with only a single group of lymph nodes involved
  • Associated with EBV
51
Q

Name 3 subtypes of classical Hodgkin’s lymphoma

A
  • Nodular sclerosing
  • Mixed cellularity
  • Lymphocyte rich and lymphocyte depleted
52
Q

Which type of Hodgkin’s lymphoma is related to NHL

A

Lymphocyte predominant Hodgkins

53
Q

What is the difference between a Hodgkin cell and a Reed-Sternberg cells

A

Hodgkin cell: mononucleated abnormal lymphocyte

Reed-Sternberg cell: bi- or multinucleated abnormal lymphocyte

54
Q

Outline some histological features of classical Hodgkin lymphoma.

A
  • Nodular sclerosis
  • Mixed cell population of Reed-Sternberg cells and Hodgkin cells
  • Lymphoma cells are few in number and are scattered around
  • Eosinophils present
  • Arise from germinal centre or post-germinal centre cells
55
Q

What are the diagnostic markers for classic Hodgkin lymphoma?

A
  • CD15
  • CD30

(CD20 negative)

56
Q

Describe the typical presentation of nodular lymphocyte predominant Hodgkin lymphoma.

A
  • Isolated lymphadenopathy
  • NO association with EBV
57
Q

Outline the key histological features of lymphocyte predominant Hodgkin lymphoma.

A
  • B cell rich nodules with scattered around L&H cells
  • Arise from germinal centres
  • Reactive population in the background consisting of small lymphocytes
  • NO eosinophils and macrophages
58
Q

Which markers are key in the diagnosis of lymphocyte predominant Hodgkin lymphoma?

A
  • Positive = CD20
  • Negative = CD15, CD30 (unlike classical Hodgkin lymphoma)
59
Q

What constitutional symptoms may be present in a patient with lymphoma?

A

B symptoms - fever, night sweats, weight loss

Pruritis

60
Q

What are the stages of lymphoma?

A

1 = 1 group of nodes

2 = > 1 group of nodes on the same side of the diaphragm

3 = > 1 group of nodes above and below the diaphragm

4 = extranodal spread

Suffic ‘B’ if B symptoms are present

61
Q

Which type of scan is often used to stage lymphoma?

A

FDG-PET/CT

62
Q

Which treatment modalities are used in Hodgkin lymphoma?

A
  • All patients receive chemotherapy
  • Radiotherapy is often used because Hodgkin lymphoma is very responsive
  • Referred to as ‘combined modality’ if both are used
63
Q

Which chemotherapy regimen is usually used for Hodgkin lymphoma?

A

ABVD: Adriamycin, Bleomycin, Vincristine, Dacarbazine

NOTE: this is usually given at 4-weekly intervals for 2-6 cycles

64
Q

What are some possible long-term consequences of chemotherapy for Hodgkin lymphoma?

A

Pulmonary fibrosis

Cardiomyopathy

65
Q

How might a relapse of Hodgkin lymphoma be treated?

A

High-dose chemotherapy with autologous stem cell transplant

NOTE: intensifying chemotherapy will lead to an increased cure rate but it will also lead to an increase in secondary cancers

66
Q

Describe the curability of Hodgkin lymphoma.

A

Stage I and II: >80%

Stage IV: 50%