Case Number : Case 710 - 6 Mar Posted By: Guest

Leishmaniasis (giemsa positive) vs. histoplasmosis (GMS positive)

Favour Leishmaniasis. Needs special stains.

Given the history-favour leish

Leishmaniasis.

Leishmaniasis

I favor leishmaniasis because the round organisms have darkly basophilic nucleus and distinct cell membrane rather than those faintly visible bodies with H&E stain in histoplasmosis. I didn’t find organisms surrounded by individual clear space dividing with narrow-based unequal buds, what would shift the balance in direction of histoplasmosis. Furthermore, parasites tend to be located at the periphery of the cytoplasm of the parasitized cell, a typical feature of leishmaniasis.
Oil immersion examination to make sure that kinetoplast is present in the organisms and use of special stains (PAS-D or GMS) will confirm the correct diagnosis.
Finally, there’s an inconsistent information from the patient: sandfly is not a “large insect”!

Thinking a little more about the “large insect” that bitted the patient while he was in a forest, I realized that the insect size could not be a fantasy or an exaggeration. Triatomid bugs are really large insects! So, this case may be an inoculation chagoma of acute American trypanosomiasis (Chagas disease). Amastigotes of [i]Trypanosoma cruzi[/i] are virtually indistinguishable from those of [i]Leishmania sp[/i]. by microscopic criteria.

Lovely comment Robeldo :-)

Leishmaniasis. This is the third or fourth such case we have seen at our county hospital in Houston in one year.