anatomical pathology: lymph nodes Flashcards
What is primary lymph node organs
Bone marrow & thymus
What happens at secondary lymph nodes
Spaces where B & T cells proliferate in response to exogenous antigen
What is the function of lymph nodes
Detect & inactivate foreign antigens present in lymph fluids
What is the flow in lymph nodes
Afferent lymphatic into subscapular sinus into medullary cords hilum into efferent lymphatic
What is the three regions of a lymph node
Cortex: nodules of B-lymphocytes with primary follicle or germinal center
Paracortex/deep cortex: T cell dependent region of lymph node
Medulla: medullar cords & sinuses into hilum
What cell is in the primary follicle
Naive & inactive B cells
What happens in the germinal center
B cell activation, proliferation & differentiation into plasma or memory cells
What important cell is in the germinal center
Tingible macrophages
What is tingible macrophages
Phagocytose cells & process antigen for lymphocyte presentation for specific immune response & removal of B cells
What is a sign of neoplastic lymph nodes
Loss of tingible macrophages
What is lymphadenopathy
Enlarged lymph nodes that can be localised or widespread & acute or chronic
What is the three causes of lymphadenopathy
Infection, autoimmune or neoplasm
What is a indication of malignant or benign
Age <30 years most likely benign
What is acute lymphadenitis
Confined to local group of nodes draining focal infection
Generalized in systemic bacterial/viral infection
When does an abscess form in acute lymphadenitis
Pyogenic organism with neutrophilic infiltrates
What is the appearance of lymph nodes in acute lymphadenitis
Usually tender but if abscess fluctuant
What is the three locations for chronic lymphadenitis
- Follicular hyperplasia
- Paracortical lymphoid hyperplasia
- Sinus histiocytosis
What & where is follicular hyperplasia & what causes it
Predominantly B cell response
Germinal center hyperplasia with marginal zone hyperplasia
Causes: syphilis or RA
What & where is paracortical lymphoid hyperplasia & what causes it
T cell response with paracortical expansion
Causes: EBV
What & where is sinus histiocytosis & what causes it
Macrophages response associated with sinus hyperplasia
Cause: unknown
What is the two main types of chronic lymphadenitis
- Granulomatous lymphadenitis
- Necrotising lymphadenitis
What is two specific infections causing granulomatous lymphadenitis
- TB
- Toxoplasmosis
What is four non-specific infections causing granulomatous lymphadenitis
- Sarcoidosis
- Chron’s disease
- Reaction to tumor antigen
- Foreign body reaction
What is the four characteristics of TB lymphadenitis
- Caseous necrosis in the centre
- Epitheloid cells
- Giant Langhan giant cells
- Collar of lymphocytes
