A number of entities, other than lymphomas and metastatic tumors, cause enlargement of the cervical lymph nodes. In a series of articles, we will discuss some of these entities, starting with toxoplasmosis.
Toxoplasmosis is the general term for infection and disease in man and animals caused by the parasitic protozoan Toxoplasma gondii. Animals affected include cattle, poultry, sheep, goats, cats, various other animals kept as pets, and various captive zoo and wild animals. In humans, the result of infection may range from asymptomatic to severe disease. Asymptomatic infection occurs both congenitally and by ingestion of infected material in immunocompetent individuals.
In congenital infection and immunosuppressed individuals, more severe forms of the disease may occur.
Lymphadenitis is the most common clinical form of the disease,
with 3-7% causing clinically significant lymphadenopathy,
particularly cervical lymphadenopathy. Thus, recognition of toxoplasmosis lymphadenitis is important (see the image below for an example). The bulk of this discussion will be on the features of toxoplasmosis lymphadenopathy.
This low-power photomicrograph shows the large, irregularly shaped germinal centers and clusters of epithelioid histiocytes found in toxoplasmosis lymphadenitis.