Lymphoma Histology Flashcards by Georgia Leggett

What are the 3 divisions of the lymphoreticular system?

Generative LR tissue: BM + Thymus
Reactive LR tissue: LN + Spleen
Acquired LR tissue: extra nodal lymphoid tissue e.g skin, stomach, lung

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What are the functions of each of the divisions of the lymphoreticular system?

Generative: generation + maturation of lymphoid cells
Reactive: development of immune reaction
Acquired: development of local immune system

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What are the cells of the lymphoreticular system?

Lymphocytes (B + T)
Accessory cells: antigen presenting, macrophages, connective tissue cells

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What are the functions of B and T lymphocytes?

B: express surface immunoglobulin + antibody production
T: express surface T cell receptor, regulation of B cell + macrophage function, cytotoxic function

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Describe the appearance of a lymphoid follicle

Paracortical T cell zone
Mantle zone: naive unstimulated B cells, dark crescent shape appearance
Germinal center: B cells, APCs

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What occurs in the germinal center?

B cells which bind antigen epitopes are selected + activated

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What is found in the paracortex as well as T cells? What occurs here?

APCs
High endothelial vessels
T cells which bind antigen epitopes are selected + activated

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How can mutation arise to contribute to the pathogenesis of lymphoma?

Normal lymphocytes undergo controlled genomic “instability” of lymphoid cells: mistakes in this produce neoplastic mutations
Inherited disorders resulting in increased/ abnormal genomic instability
Viral agents: EBV, HTLV1
Environmental agents: mutagens, chronic immune stimulation (e.g H pylori)
Iatrogenic: radiotherapy, chemotherapy

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How does immunosuppression predispose to development of lymphoma? Give an example

Infection e.g. HIV
Loss of surveillance

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What is the most common type of lymphoma?

B cell non-hodgkin lymphoma (80-85%)

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Why are lymphoid cells often disseminated at presentation?

Neoplastic lymphoid cells circulate in blood
(Exception = Hodgkins (presents as defined, localised) + some very early NHL)

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Why do some patients with lymphoma develop immunodeficiencies?

Lymphoid neoplasms may disrupt normal immune system

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How can pathologists assess cells for malignancy?

Cytology: single cells aspirated from a lump
Histology: tissue sections architecture + cell shape/ size

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What may you suspect from finding small round lymphocytes on histology?

Naive B cells:
CLL or Mantle cell lymphoma

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What may you suspect from finding small cleaved lymphocytes on histology?

Follicular lymphoma

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What may you suspect from finding large lymphocytes with prominent nuclei on histology?

High grade lymphoma

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What is immunohistochemistry used for? How?

Identifies proteins on/ in cells in tissue sections
Uses labelled antibody to cell surface receptor

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Which markers indicate whether lymphomas are B cells or T cells?

B cell: stain +ve with antibodies to CD20
T cell: stain +ve with antibodies to CD3 or 5

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What can be determined on immunohistochemistry?

Cell type
Cell distribution
Loss of normal surface proteins e.g. CD3 in neoplastic T cells
Abnormal expression of proteins e.g. Cyclin D1 (Mantle cell lymphoma)
Clonality of B cells (light chain expression)

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What is meant by clonality of B cells?

A reactive population of B cells will express both Kappa + Lambda light chains
In lymphoma, a population will exclusively express kappa OR lambda

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What molecular tools can be used in lymphoma?

FISH: identifies Chr translocations
PCR: identify Chr translocations + clonal T cell receptor or immunoglobulin gene rearrangement

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Give an example of a diagnostic translocation that may be determined by FISH

11:14 Mantle cell lymphoma

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Give an example of a prognostic translocation that may be determined by FISH

2:5 Anapaestic large cell lymphoma

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Give 3 examples of low grade B cell non-hodgkin lymphomas

Follicular lymphoma
Small lymphocytic lymphoma/ CLL
Marginal zone lymphoma

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Give 2 examples of high grade B cell non Hodgkin lymphoma

Diffuse large B cell lymphoma Burrito's lymphoma

Is Mantle cell lymphoma categorised in B cell NHL?

Aggressive Composed of small/ medium cells (as would be seen in low grade) but is aggressive

What can be seen on histopathology in follicular lymphoma?

Follicular pattern Express B cell markers: CD20 Germinal centre cell origin :CD10 + BCL6 +ve

What translocation is found in molecular studies of follicular lymphoma?

14;18 translocation involving BCL2 gene (BCL2 expressed in neoplastic follicle- should only be in mantle)

Give 2 features of follicular lymphoma

Lymphadenopathy in MA/ elderly Indolent but can transform to high grade

How do small lymphocytic lymphoma and CLL differ in presentation?

Lymphadenopathy: small lymphocytic lymphoma High WCC: CLL

What can be seen on histopathology in small lymphocytic lymphoma / CLL?

Small lymphocytes: Naive or post germinal center memory B cells Abnormal expression of CD5 + CD23 +ve

What may be found in molecular studies in small lymphocytic lymphoma/ CLL?

Multiple genetic abnormalities

Give 2 features of small lymphocytic lymphoma/ CLL

MA or elderly Indolent but can transform to high grade= Richter transformation

Where do marginal zone lymphomas (MALT) usually arise?

Extranodal sites e.g. gut, lung, spleen In response to chronic antigen stimulation + inflammation

What cells are present in MALT?

Post germinal centre memory B cells

Describe the nature of MALT

Indolent but can transform to high grade Can treat low grade with non-chemotherapeutic modalities- eradicate antigen

Give 3 features of mantle cell lymphoma presentation

MA M > F Lymphadenopathy + Weight loss Disseminated disease at presentation

What may be seen on histopathology in mantle cell lymphoma?

Pre-germinal center cells located in mantle zone Aberrant CD5 + Cyclin D1 expression

What is found in molecular studies in mantle cell lymphoma?

11;14 translocation Cyclin D1 over-expression

Give 2 features of Burkitt's lymphoma presentation. Describe the aetiology

Jaw or abdo mass in children/ YA Endemic: SS Africa Sporadic Immunodeficiency: in context of HIV EBV associated

What is found on histopathology in Burkitt's lymphoma?

Germinal center cell origin "Starry-sky" appearance

What is found in molecular studies in Burkitt's lymphoma?

C-yc translocation 8;14 2;8 8;22

Give 2 clinical features of diffuse large B cell lymphoma

MA/ Elderly Lymphadenopathy

What is found on histopathology in diffuse large B cell lymphoma?

Germinal center/ post-GC B cells Sheets of large lymphoid cells

What histopathologic findings in diffuse large B cell lymphoma are prognostic?

GC phenotype (CD10 +ve) = GOOD p53 +ve, high proliferation = POOR

Give 5 features of peripheral T cll lymphomas NOS

MA/ elderly Lymphadenopathy + extra nodal sites Large T lymphocytes Associated with reactive cell pop, esp. eosinophils Aggressive

List 4 special forms of T cell lymphoma

Adult T cell leukaemia/ lymphoma Enteropathy associated T cell lymphoma Cutaneous T cell lymphoma Anapaestic large cell lymphoma

In which populations are adult T cell leukaemia/ lymphoma more common?

Caribbean + Japan Associated with HTLV-1 infection

Give 3 clinical features of anapaestic large cell lymphoma

Children/ YA Lymphadenopathy Aggressive

What is seen on histopathology in anapaestic large cell lymphoma?

Large "epitheliod" lymphocytes T cell or null phenotype (express no T or B markers)

Give 2 molecular findings in anapaestic large cell lymphoma

2;5 translocation Alk-1 protein expression (better prognosis)

Give a type of cutaneous T cell lymphoma. What happens?

Mycosis fungoides CD4 +ve T cells infiltrate epidermis Form micro-abscesses Plaques + patch phase Nodular stage: of abnormal T cells

Differentiate between Hodgkins + non Hodgkins lymphoma

H: usually localised to single nodal site + spreads contiguously to adjacent LN NHL" usually involves multiple LNs, spreads discontinuously

List 4 subtypes of classical Hodgkins lymphoma

Nodular sclerosing Mixed cellularity Lymphocyte rich Lymphocyte depleted

Name 1 non-classical type of Hodgkins lymphoma

Lymphocyte predominant (some relationship to NHL)

Give 3 clinical features of classic Hodgkins lymphomas

Young + MA Often just single LN group EBV associated

Where do cells originate in classical Hodgkins lymphoma?

Germinal center or Post GV B cells CD30 +ve CD15 +ve CD20 -ve

What is seen on histopathology in classical Hodgkins lymphoma?

Sclerosis Reactive mixed cell population in which scattered Reed-Sternberg + Hodgkin cells with eosinophils

Give 4 features of non classical lymphocyte predominant Hodgkins lymphoma

Lymphadenopathy No association to EBV Indolent Can transform to high grade

Where do cells originate in non classical lymphocyte predominant Hodgkins lymphoma?

Germinal center B cells (+ve for some GC B cell markers e.g. CD10, BCL6) CD30 -ve CD15 -ve CD20 +ve

What is seen on histopathology in non classical lymphocyte predominant Hodgkins lymphoma?

B cell rich nodules with scattered L+H cells

Lymphoma Histology Flashcards

(61 cards)