Toxoplasma Lymphadenitis: Toxoplasma trophozoites are rarely seen in the lymph nodes of immunocompetent patients with routine H&E morphology, immunostains, or by PCR. In immunocompromised patients, such as patients with AIDS, clusters of crescentic shaped trophozoites free or in macrophages may be seen. They are best detected in Giemsa-stained tissue imprints or smears. Chronic cases of toxoplasmosis may rarely show cysts within involved lymph nodes. In cases with presumptive diagnosis of toxoplasma lymphadenitis on a lymph node biopsy or FNA, serologic studies are helpful in confirming the diagnosis. This image from a case of toxoplasma lymphadenitis shows monocytoid B-cells in a sheet (left half) and aggregates of epithelioid histiocytes (right half).