(This is another continuation of the Sabah Lymphoma talk -- first and second part)
I. Toxoplasma
I. Toxoplasma
- Three features:
- Follicular hyperplasia.
- Epithelioid histiocytes.
- Monocytoid B cells in sinusoids.
- Enlarged germinal centre (still have mantle zone and tingible body macrophages)
II. Viral
- Partial architectural effacement with expanded paracortex.
- Polymorphous cellularity.
- Mottled histological appearance with marked follicular hyperplasia.
- Infectious mononucleosis
- Expanded paracortez with heterogenous population.
- Increased blood vessels.
- Presence of immunoblasts that mimic Reed-Sternberg cells.
- Hyperplastic follicles.
- Herpes simplex virus
- Mixed cell population.
- Reed-Sternberg-;ole activated lymphocytes.
- Apoptotic cells and neutrophils.
- HIV
- Early: present with acute reactive lymphadenitis.
- Late: present with marked CD4+ T-cell depletion, and involution of lymph nodes.
- 3 phases:
- Acute
- Non-specific, more to viral lymphadenitis, eg paracortical expansion.
- Transition
- Disruption of normal architecture, germinal centre smaller, excessive pool of blood vessels.
- Burn-out
- Atrophic.
III. Bacterial
- Composed of sinus expansion.
- May contain proteinaceous fluids or microabscesses
- eg Cat-scratch disease, tuberculosis.
Below is not an infective condition but important anyway:
Epithelial cell inclusion in lymph node
- May include squamous, thyroid, mammary glands
- Must differentiate from metastasis.
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