Saturday, March 26, 2016

Case of the Week 390

The week's case was generously donated by Blaine Mathison. Below are H&E-stained sections of a perineal abscess of a patient diagnosed with Fournier's gangrene with bacterial infection. Identification?
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15 comments:

nucleus accumbens said...

Are they sarcopte's eggs ? ( Happy Easter )

nucleus accumbens said...

Are they sarcopte ' s eggs ? (happy easter)

Anonymous said...

The morphology with a peripheral ring of nuclei of variable size is compatible to Blastocystis hominis. Actually the nuclei are rather on the cellular membrane. I often liken these to a clear membrane onto which someone has affixed a few dabs of play dough.

Florida Fan

PCoyne said...

Acanthamoeba

Paul S said...

LDD or little dot disease! But the differential for LDD is pretty small in my mind ( I am a simple clinician so excuse my ignorance) Leishmaniasis, T. cruzi, amoeba and that non pathogen (unless you're the one sick with it) B hominis. Given the nuclei in the cytoplasmic rim, I agree with B hominis. And yes I'd treat it even if it just got there with all the bacteria from the gut from poor hygiene or a fistula that caused the gangrene.

Anonymous said...

I thought Blastocystis hominis as well.

Lee

Anonymous said...

I agree with B. Homs.

Jacque

Christen Rune Stensvold said...

Beautiful images! Blastocystis of course! But why? Probably secondary "invasion", although invasion should be used with caution here, since bacteria may have paved the way for the parasite. The interesting thing is that it says "perineal" and not "perianal"... if the abscess had been "perianal", the finding might have been quite unsurprising; however, the fact that it's a "perineal" abscess makes it a bit more tricky and interesting. Was any anal fistula involved that could facilitate passage of Blastocystis from the rectum to the perineal abscess?

Anonymous said...

Sure looks like Blasto. However, the source information makes me nervous to call it that though, since I have never heard of Blasto in an abscess.

~Micro Michigan

Anonymous said...

Acanthamoeba skin infection; cysts and trophs

Arthur Morris said...

Well, based on morphology alone my differential is Acanthamoeba and Blastocystis. On morphology, Blastocystis gets it. The peripheral nuclei and vacuole are very clear in these pictures. The presentation is perhaps more in line with an invasive Acanthamoeba infection, and there are some bodies in the third image which look a little like they bear the 'rippled star edges' that you see in Acanthamoeba cysts. Having said all of this though, the diagnosis must go to Blastocystis in morphology alone. As for it causing the infection and gangrene, I doubt that. I have not heard of this kind of presentation in Blasto before, but it is possible that whatever means Blasto used to infiltrate the peripheral tissue could have been utilised by pyogenic bacteria too.

Great case, I am very interested to hear what you have to say on it Bobby.

Anonymous said...

Blastocystis sp.

Anonymous said...

Blastocystis hominis.

jody fleming said...

I agree with others. B. hominis

mona said...

blastocystis hominins ?!!!