Haem: Lymphomas 1 - Multidisciplinary Flashcards
What is lymphoma?
tumour of lymphoid cells
What are the 2 types of lymphomas and which is more common?
80%= Non-Hodgkin’s 20%= Hodgkin’s
What are the 2 other ways of classifying lymphoid malignancies?
T or B cell (myeloid) lineage
Have precursor haematopoietic malignancies or Have mature lymphoid malignancies
What are the 3 reasons lymphocytes have such a high risk of developing maligancies?
1- Go through several point mutations that there is a high potential for recombination errors
2- Hyperproliferation so higher chances of DNA replication error
3- Rely on apoptosis. If mutation turns off apoptosis - DANGER
What happens in somatic hypermutation?
VDJ recombination - Class switching (from IgM to IgG/IgA)
How is there an over-expression of oncogenes in lymphomas?
A B cell that is tuned to respond to antibody will have a highly active immunoglobulin promoter (which sits upstream of the rearranged immunoglobulin molecule), with the purpose of driving antibody production.
However, if there has been a recombination error (e.g. when switching from IgM to IgG), the DNA being translocated and recombined may have pro-oncogenic potential.
These cell-promoting oncogenes can get translocated (due to error) downstream from the immunoglobulin promoter.
What are 3 risk factors for lymphoma?
Constant antigenic stimulation - Due to infections or autoimmune diseases
Viral infections
Loss of T cell fx - HIV killing T cells or Iatrogenic immunosuppresion
(Lose the sureveillance effect of cytotoxic T cells)
What are some examples of chronic antigen stimulation?
B cell Non-Hodgkin’s Lymphoma- Marginal Zone Subtype (MZL)
- H pylori Gastric MALT - Sjogren's - MZL of parotid - Hashimoto's - MZL of thyroid
Enteropathy associated T-cell Non-Hodgkin’s lymphoma (EATL)
- Due to coeliac
How does HTLV1 affect T cells and how can it present?
Vertical transmission and after a lifetime of carrying it, they can present neurologically as Tropical Spastic Paraparesis
What kind of T cell lymphomas can HTLV1 cause and how does it present?
ATLL - lymphadenopathy, hepatosplenomegaly, skin lesions + hypercalcaemia
What are the 2 ways in which viral infections can give rise to post-transplant or immunosuppression-associated B cell lymphomas?
EBV- drives B cell proliferation
HIV- leads to loss of T cell function (or loss of function via steroids, immunosuppression etc.)
What happens in Iatrogenic (transplant immunosuppression)- Post-transplant lymphoproliferative disorder?
Loss of T cell function
What are the 3 lymphoreticular tissues?
Generative lymphoreticular tissue
Reactive lymphoreticular tissue
Acquired lymphoreticular tissue
What are the 2 types of cells in the lymphoreticular system?
Lymphocytes - T and B cells
Accessory cells - Antigen presenting cells
Explain where and how B cells mature?
They mature in the bone marrow.
Naive B cells enter the lymph nodes and reside in the mantle zone. They then enter the germinal centre where their maturation and proliferation begins. This is where most things can go wrong.
What are the 2 types of cells B cells can grow into?
Antibody secreting plasma cells
Memory B cells
Where do T cells develop and what are the 2 types they can develop into?
Thymus
CD8+ cytotoxic cells
CD4+ helper cells
What are the main cell markers expressed by B cells?
CD20
What are the main cell markers expressed by T cells?
CD2, CD3 and CD5
What are the main cell markers expressed by early lymphocytes developing in the bone marrow?
CD 34 and TDT
What are the main cell markers expressed by lymphocytes in the germinal / follicular centres of lymph nodes?
CD10 and BCL-6
Why does immunosuppression increase the risk of lymphomas?
Predisposed to infection
Loss of surveillance of cell replication
What are the 2 ways of classifying lymphomas
Hodgkins and non Hodgkin
What are the 2 ways of classifying Hodgkins
Classical
Lymphocyte predominant
What are the 2 ways of classifying non - Hodgkins
T cell
- Precursor T cell neoplasm
- Mature/ Peripheral T cell neoplasm
B Cell
- Precursor B cell neoplasm
- Mature/ Peripheral B cell neoplasm - Low or high grade
Why does Non Hodgkins tend to not be disseminated?
As it affects only one or two lymph nodes
Which cells give rise to CLL
Naive B cells
What is multiple myeloma?
Sheets of cells that resemble normal plasma cells and secrete abnormal amounts of antibodies
When looking at tissue architecture, if it is nodular, what type of lymphoma could it be?
Follicular
When looking at tissue architecture, if it is diffuse, what type of lymphoma could it be?
CLL
When looking at tissue cells, if it is small and round, what grade of lymphoma could it be?
Low
If round, small and uniform - CLL
When looking at tissue cells, if it is small and cleaved, what type of lymphoma could it be?
Mantle cell or follicular
When looking at tissue cells, if it is large, what grade of lymphoma could it be?
High
When looking at tissue cells, if it is large with large nuclei and prominent nucleoli, what type of lymphoma could it be?
Burkitt’s
Diffuse B cell
What does CD20 in the mantle zone suggest?
Mantle zone lymphoma
What markers do neoplastic T cells have?
None, they lose normal surface proteins
What abnormal proteins do B cells express in mantle cell lymphoma?
Cyclin D1
What light chains do B cells usually express?
A mixture of K and Lamba light chains
What light chains do B lymphoma cells usually express?
K OR Lamda light chains EXCLUSIVELY
What molecular tools are used to diagnose lymphomas?
FISH
PCR
What are the low grade Non-Hodgkins lymphomas?
Follicular
CLL
Mantle zone
What are the high grade Non-Hodgkins lymphomas?
Burkitt’s
Diffuse large B cell
What are the aggressive Non-Hodgkins lymphomas?
Mantle cell
How does follicular lymphoma present?
Lymphadenopathy in middle aged or elderly
What does the follicular pattern for follicular lymphoma look lie?
Neoplastic nodules
Normal follicular cells appearance but irregularly shaped nuclei
What do follicular lymphoma cells stain for?
CD10
BCL 6
BCL 2 (Normal follicles DO NOT express this)
What is the main difference between CLL and Small Lymphocytic Lymphoma
SLL - Lymph nodes and tissue forming masses
CLL - High WCC
What do you see on histo for CLL and SLL
Sheets of small uniform lymphocytes
There are perfectly round nuclei and chromatin pattern
They replace the entire lymph node so that you no longer see follicles or T cell areas
What cells do CLL and SLL arise from?
Arises from naïve B cells or post-germinal centre memory B cells
What cell markers do CLL and SLL have?
These cells are CD5 and CD23 POSITIVE
NOTE: CD5 should never be seen in a normal B cell
What is Richter transformation?
CLL transforming into higher grade lymphoma
Where do marginal zone lymphomas arise at?
Extra nodal sites
Where do marginal zone lymphomas arise from?
Post germinal centre memory B cells
Why do marginal zone lymphomas arise and how can they be treated?
Chronic antigenic stiumaltion
Removal of such stimulation can treat this lymphoma
How does Mantle cell lymphoma present?
Lymphadenopathy and large polyps in large bowel and other GIT disturbances
What does the histo for Mantle cell lymphoma show?
Mantle zone
Arise from pre germinal centre cells
What cell markers are aberrantly expressed by Mantle cell lymphoma?
CD5 and cyclin D1
What translocation is Mantle cell lymphoma associated with?
11;14
Cyclin D1 overexpression
How does Burkitts lymphoma present?
Jaw or abdo mass
What diseases are associated with Burkitts lymphoma
EBV
HIV
What cells do Burkitts lymphoma arise from?
Germinal centre cells
What is the classic histo appearance for Burkitts lymphoma?
Starry sky appearance
What translocation is seen in Burkitts lymphoma
c-Myc
What is the histo for Diffuse Large B cell Lymphoma
There are sheets of LARGE lymphoid cells
There are pleiomorphic nuclei, prominent nucleoli
There are many mitotic figures
The lymph node is effaced so it is NOT possible to identify germinal centres and follicles
What are the 2 types of cells Diffuse Large B cell Lymphoma can arise from?
Germinal centre OR post germinal centre B cells
What do Diffuse Large B cell Lymphoma arising from germinal centres express
CD10 and Bcl 6
What do the poor and good prognosis of Diffuse Large B cell Lymphoma show?
Having a germinal centre phenotype is associated with a GOOD prognosis
p53 +ve and high proliferation fraction is associated with a POOR prognosis
How do T cell lymphomas present?
lymphadenopathy and extranodal sites
Large T lymphocytes
Often found with an associated reactive cell population (especially eosinophils, plasma cells)
What is the histo for Adult T cell leukaemia/ lymphoma look like?
Associated with HTLV-1 infection
Nuclei of the cells often resemble clover-leaves in the peripheral blood (known as flower cells)
Who commonly gets Enteropathy-associated T cell lymphoma and how does it present?
Occurs in some patients with long-standing coeliac disease
This arises from intra-epithelial T cells
What causes Cutaneous T cell lymphoma and how does it present?
E.g. mycosis fungoides
The lymphoma cells will infiltrate the epidermis in the early stages, forming raised plaques
In later stages, the cells form nodules in the dermis
How does Anaplastic Large Cell Lymphoma usually present?
Children and young adults
Lymphadenopathy
What does the histo for anaplastic large cell lymphoma look like
Atypical large epithelioid lymphocytes
T cell or null phenotype (e.g. anaplastic)
Very variably sized nuclei and oddly shaped (i.e. kidney, long stretched)
What cell markers does anaplastic large cell lymphoma usually express?
CD30
What is the genetic translocation usually associated with anaplastic large cell lymphoma
2;5
Alk-1 protein expression
What are the main difference betwenn NHL and HL?
HL usually invovles just one node
HL spread contagiously to adjacent lymph nodes
NHL tends to involve multiple lymph node sites and spreads discontinuously
How does Classical Hodgkin’s Lymphoma usually present?
Young and middle-aged
Often involves just a single group of lymph nodes
Arises from the germinal centre or post-germinal centre cells
Associated with EBV
What is the histo for classical HL look like?
Mixed cell population with Reed-Sternberg and Hodgkin cells
Lymphoma cells are RELATIVELY FEW in number and tend to be scattered around
The infiltrate have many reactive cells e.g. eosinophils (along with macrophages, plasma cells etc.)
Show large nuclei with prominent nucleoli (often multi-nucleate- ‘Owl’s eye appearance’)
What are the cell markers for Classical HL?
CD30 and CD15
NEGATIVE FOR CD20!!!
How does Nodular Lymphocyte Predominant Hodgkin’s Lymphoma present?
Isolated lymphadenopathy
Arise from the germinal centre B cells (which will stain POSITIVE for some germinal cell B ell markers)
NO association with EBV
What is the histo for Nodular Lymphocyte Predominant Hodgkin’s Lymphoma
look like?
B cell rich nodules
Scattered around L&H cells
The reactive population in the background will be just small lymphocytes
You do NOT see eosinophils or macrophages like you would in classical Hodgkin’s
What is to be noted for Nodular Lymphocyte Predominant Hodgkin’s Lymphoma?
It can transform into NHL
What are the cell markers for Nodular Lymphocyte Predominant Hodgkin’s Lymphoma?
POSITIVE FOR CD20
NEGATIVE FOR CD30 AND CD15
What disease is Marginal zone lymphoma of parotid linked to?
Sjogren’s syndrome due to chronic antigenic stimulation
What does ciclosporin therapy usually lead to?
EBV driven post transplant lymphoma
