Lymphadenopathy Flashcards
What part of the lymph node is affected in RA and early HIV?
Follicles
What area of the lymph node is affected in a viral infection?
Paracortex (e.g mono)
What part of the lymph node is affected in cancer
Sinus histiocytes (in medulla) - draining issue
What is a lymphoma?
Neoplastic proliferation of lymphoid cell that form a mass
- May arise in LN or in extranodal tissue
What is follicular lymphoma?
- Neoplastic small B cells (CD20+) that make follicle-like nodules
- Clinically presents in late adulthood with painless, generalised LAD
What translocation is associated with follicular lymphoma?
What does this lead to?
t(14;18)
- BCL2 on chromosome 18 translocates to Ig heavy chain locus on chromosome 14
- Results in overexpression of Bcl2, which inhibits apoptosis
What process in the follicle of the lymph node requires apoptosis?
Somatic hypermutation
- Cells that fail somatic hypermutation must undergo apoptosis - if Bcl2 is overexpressed the B cells of the follicle that fail cant undergo apoptosis
How is follicular lymphoma treated?
- Low dose chemo
- Rituximab
Asymptomatic patients (many) are not usually treated
What is the major complication associated with follicular lymphoma?
Diffuse large B-cell lymph node
What is the difference between follicular lymphoma and hyperplasia?
- Hyperplasia may occur with infection
- Follicular lymphoma there is a lack of tingible body macrophages in germinal centre (white spaces)
- Follicular Lymphoma has expression of Bcl2 in follicles
- FL has monoclonality
Reactive proliferation of lymphocytes
Polyclonal - ratio of kappa to lamda light chain 3:1
Neoplastic proliferation of lymphocytes
Monoclonal - ratio of kappa to lamda light chain ~ 20;1
What is Mantle cell lymphoma?
- Neoplastic small B cells (CD20+) that expand the matle zone (region immeadiately adjacent to the follicle)
- Clinically presents in late adulthood w. painless LAD
Mantle cell lymphoma is associated with what translocation?
And what does this result in?
11;14
- Cyclin D1 on chr 11 translocated to Ig heavy chain locus on chromosome 14
- Overexpression of cyclin D1 promotes G1/S transition in cell cycle
What does cyclin D1 do?
Cell cycle regulator which helps the cell go from G1 to S phase - it does this by phosphorylating proteins
What is a marginal zone lymphoma?
Neoplastic small B-cells (CD20+) that expand marginal zone
What kind of diseases is marginal zone lymphoma associated with?
- Hashimoto’s thyroiditis, Sjorgen syndrome, H pylori gastritis
- Marginal zone is formed by post-germinal center B-cells
What kind of lymphoma is H pylori associated with?
Marginal zone lymphoma in mucosal sites (e.g stomach)
(MALToma)
- Gastric maltoma may regress with treatment of H pylori
What is Burkitt Lymphoma?
Neoplastic intermeadiate-sized B cells (CD20+)
- Associated with EBV
- Extranodal mass in child or young adult
Where do the different forms of Burkitt lymphoma present?
- African form usually involves jaw
- Sporadic form usually involves abdomen
What kind of translocations are involved in Burkitt lymphoma?
- Driven by translocations of c-myc (chr8)
- t(8;14) is most common
- Results in translocation of c-myc to Ig heavy chain locus on chr14
- Overexpression of c-myc oncogene which promotes cell growth
Describe the histology in Burkitt Lymphoma
Starry sky appearence (due to high mitotic rate)
- Macrophages eat away at cells while they die
What is diffuse large B cell lymphoma (DLBCL)?
- Neoplastic large B-cells (CD20+) that grow diffusely in sheets
- Presents in late adulthood as an enlarging LN or extranodal mass
- Most common of all NHL
- Clinically aggressive
What can DLBCL arise from?
Follicular lymphoma
What cells are involved in Hodgkin lymphoma?
Reed-Sternberg cells
- Secrete cytokines which draw in other inflammatory cells (lymphocytes, plamsa cells, macrophages and eosinophils) - this is what produces the mass
Describe the Reed-Sternberg cell
Large B cell with multilobed nuclei and prominent nucleoli
- CD 15 and 30+
- Looks like an owl
What are the subtypes of Hodgkin lymphoma?
- Nodular sclerosis (70%)
- Lymphocyte-rich
- Mixed cellularity
- Lymphocyte-depleted
What are the subtypes of Hodgkin lymphoma?
- Nodular sclerosis (70%)
- Lymphocyte-rich (best prognosis)
- Mixed cellularity (abundant eosinophils, IL-5)
- Lymphocyte-depleted (worst prognosis, elderly and HIV+ often)
Describe the classic presentation of Nodular sclerosis Hodgkin lymphoma?
Enlarging cervical neck or mediastinal LN in a young adult, usually female
What will the biopsy of nodular sclerosis Hodgkin lymphoma reveal?
Lymph node divided by bands of fibrosis (pink)
- RS cells are present in late-like spaces (lacunar cells) (they sit in big open spaces on histology)
