Lymph Node Pathology Flashcards
What are the primary lymphoid organs?
bone marrow and thymus
What are the secondary lymphoid organs?
lymph nodes, spleen, MALT
Where is MALT found?
tonsils, adenoids, airways, gut
What is found in the paracortex of a lymph node?
naive T cells
high endothelial venules
interdigitating dendritic cells
What is found in a lymph node primary follicle?
naive B cells
follicular dendritic cells
T cells
What is found in the mantle zone of a lymph node?
Naive B cells
What is found in the medullary cords of a lymph node?
Small T and B lymphocytes,
immunoblasts,
plasma cells
What is found in the sinuses of a lymph node
lymph
macs
small B and T lymphocytes
What happens to naive B cells in a germinal centre?
stimulation -> naive B cells from mantle zone undergo clonal expansion + differentiation to centroblasts -> centrocytes -> immunoblasts -> somatic hypermutation + class switching -> migration to medullary cords -> differentiate into plasma cells -> few become memory B cells
T/fL Naive B cells and FDCs are the only cells found within germinal centres
False. Cells within the GC include naive B cells, follicular dendritic cells (FDCs), macs and Helper T cells.
What are some causes of lymphadenopathy?
localised infection in the area of drainage
systemic infections, usually viral
non-infective systemic disease eg RA, SLE, sarcoidosis
drugs
lymphomas
leukaemic infiltration
metastases
Histopathologic pattern of Acute non-specific lymphadenitis?
PMN infiltration, oedema, follicular hyperplasia
nodes are large and painful
Histopathologic patterns of Chronic non-specific lymphadenitis?
- follicular hyperplasia
- paracortical: proliferation and activation of T cells
- sinus histiocytosis: incr macs in sinuses
- granulomatous inflammation
- mixed patterns
Causes of neoplastic lymphadenopathy?
- Primary tumours: Hodgkin/non-Hodgkin lymphoma
- Secondary tumours (mets) more common: carcinomas, melanomas, germ cell tumours
- Leukaemic infiltration
