Sunday, August 23, 2015

Case of the Week 361

The following specimen was submitted to the laboratory for identification (CLICK ON IMAGES TO ENLARGE):

Using gentle manipulation with forceps, the following were expressed from this object: 

How would you go about identification to the species level in your laboratory? (I'm especially interested in hearing what your specific practice is). Thanks!


Fernando Barahona said...

It seems Taenia solium. I don't have a lab unfortunately.

Arthur Morris said...

Taenia sp. but without further analysis of the proglottid or occasionally scolex morphology it is not possible to tell which. The general methods I have used in the past are H&E staining or, a slightly quicker method, sandwiching the proglottid between two slides and carefully pipetting a small amount of india ink into the genital pore to show the uterine branches nicely. After this it is just a case of counting the branches and coming to an identification after that.

Anonymous said...

Taenia sp.
Sandwichmethod using a petridish then examine under stereo microscope

Bobbi Pritt said...

Thank you for the comments!

Arthur, do you find the India ink injection method to usually be successful in your hands? And do you have any luck injecting proglottids that come in formalin or ethanol? Our specimens often come in one of these preservatives which makes it challenging to inject the India ink into the genital pore. Clearing the proglottid in phenol first would probably help soften it up and facilitate injection, but we find this to be a manual and lengthy process. Recently we've been having more success with histologic processing and sectioning. I'm just curious to hear what others are doing and what works best in their hands.

Anonymous - when you use the sandwich method, do you find that you are able to visualize the branches without India ink injection? Also, do you first clear the proglottids in phenol?

Anonymous said...

For sure this is a case of Toenia sp. infection. The sure clue to the toenia solium is the armed rostrum, which does not happen often as we mostly receive a part of the worm. Without the scolex, we use the pressing and clearing to count the main branches of the uterus. Historically we could stain the proglotids with Semichon's Carmine or we can inject India Ink into the median uterine followed by clearing to facilitate the observation.
Unfortunately, we are so cost reduction focused that the practices have been eliminated. This makes our identification more challenging and the quality of the training of our new technologists even more elusive.

Florida Fan

Arthur Morris said...

Hi Bobbi

I rarely use this method since my work rarely calls for it, but the times I have done it it has been successful enough to visualise the uterine branches. I find it more difficult to do after the specimen has been formalised because of the change in consistency to something resembling rubber which I don't seem to get so much in ethanol. I can rarely see anything before staining unless it is a very fresh sample, I usually received them in formalin which seems to make them contract, obscuring obvious morphology. I would usually go for a histo stain, especially if there is a limit amount of the specimen to work with and given how funny the other methods can be in practice, but if there is a lot of the sample I might try a squashed India ink method first on the off chance it saves me some time!

Hope this helps

Anonymous said...

We are no longer parasite qualified (but my strongyloides case shows you how that goes in reality LOL), but I would attempt an india ink prep before sending to Mayo for definitive ID. Taenia.


Chris Gatward said...
This comment has been removed by a blog administrator.
Bob N. said...

We had a case where a elderly Thai women had stool submitted for C.diff. and a two foot long tapeworm segment came along with it. We cleared the proglottids with glycerine, and could count the branches. At first we though T. saginata but our pathologist thought it was T. asiatica - very interesting case.

Unknown said...

In our lab, we sandwich between 2 slides and hold up to the light and count the branches, therefore no need to inject ink