14 June 2007 – Case of the Week #87
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Case of the Week #87
A 41 year old HIV+ man from Central America presented with pancytopenia and skin nodules. A bone marrow biopsy was performed.
What is your diagnosis?
Visceral leishmaniasis is caused by the protozoan parasite Leishmania donovani and transmitted by the bite of the infected sandfly Phlebotomus argentipes (life cycle). It primarily affects HIV+ / immunocompromised patients, and immunocompetent patients in endemic areas (South America, India, Northeast Africa, Mediterranean basin). It is a parasitosis of the mononuclear phagocytic system, and causes fever, hepatosplenomegaly, hypergammaglobulinemia and pancytopenia.
Definitive diagnosis is made by PCR (J Clin Microbiol 2006;44:2343), or antibody / antigen testing. Smears or H&E sections are often suggestive, as in this case. The bone marrow is hypercellular with erythroid hyperplasia and often dysplastic changes in normoblasts. Smears show amastigotes (the form that exists in humans) within macrophages and occasionally granulocytes. The amastigotes have a distinct kinetoplast (image), which represents mitochondrial DNA (see images). The differential diagnosis of parasites within macrophages includes histoplasmosis (see images) and toxoplasmosis (see images). The current recommended treatment is sodium stibogluconate administration.
Nat Pernick, M.D., President
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