( This is another continuation of the Sabah Lymphoma talk -- first and second part ) 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 exp...