Lymph nodes & spleen, nonlymphoma
Lymph nodes-infectious / parasitic disorders

Topic Completed: 1 June 2006

Minor changes: 4 November 2020

Copyright: 2003-2021,, Inc.

PubMed Search: Toxoplasmosis[TI] lymph nodes

Page views in 2020: 10,779
Page views in 2021 to date: 851
Cite this page: DePond W Toxoplasmosis. website. Accessed January 24th, 2021.
Definition / general
Diagrams / tables

Images hosted on other servers:

Life cycle

  • Based on morphology and serology (IgM antibody), as PCR and immunostains are usually negative in lymph nodes
  • High IgG avidity only in patients who developed lymphadenopathy at least 4 months earlier (J Clin Microbiol 2004;42:4627)
Case reports
  • Pyrimethamine and either sulfadiazine or clindamycin
Microscopic (histologic) description
  • Well preserved nodal architecture (J Clin Pathol 1961;14:565)
  • Marked follicular hyperplasia with frequent mitotic figures and phagocytosis of nuclear debris, small noncaseating epithelioid granulomas with indistinct margins (presence within germinal centers is fairly specific for toxoplasmosis), distention of sinuses by monocytoid B cell with immunoblasts and plasma cells in medulla
  • Occasionally granulomas exhibit necrosis or have frequent Langhans giant cells
  • Recommended diagnostic criteria are either (1) florid reactive follicular hyperplasia, clusters of epithelioid histiocytes and focal sinusoidal distention by monocytoid B cells (Pathol Int 2001;51:619) or (2) microgranulomas, absence of giant cells, lower than grade 2 macrogranuloma and follicular hyperplasia (J Clin Pathol 2005;58:1143)
Microscopic (histologic) images

AFIP images

Toxoplasmic lymphadenitis

Contributed by Dr. Mark R. Wick

Toxoplasma lymphadenitis

Images hosted on other servers:

Epithelioid histiocytes and necrotic fragments

No reticulin present

Monocytoid cells

Plasma cells in nodal capsule

Toxoplasma cyst at margin of follicle

shows trophozoite-like
bodies (arrows)

Cytology description
  • Epithelioid microgranulomas (small clusters of epithelioid histiocytes with abundant, pale staining and homogenous cytoplasm and eccentric, oval nuclei but no necrosis, giant cells or neutrophils) are characteristic (Acta Cytol 2005;49:139)
  • Reactive hyperplasia and tachyzoites within lymphocytes (Acta Med Croatica 2005;59:153)
  • Pap stain may demonstrate parasite on FNA (Acta Cytol 2003;47:299)
Back to top
Image 01 Image 02