Case of the Week 320

Multiple motile small white objects were found in the diaper of an infant.  The specimens were submitted to surgical pathology where they were fixed in formalin, sectioned, and the resultant slides were stained with H&E.  Below are representative sections taken at 20x to 1000x final magnification).  Identification?

Answer to Case 320

Answer:  Dipylidium caninum proglottids containing numerous egg packets.  Each of the small structures shown in the low power images is a (very) gravid proglottid:

On higher magnification, the characteristic eggs packets are seen, each containing eggs with hooklets (you have to use your imagination a bit to see the hooklets).

Although the eggs look a little different than what we see in stool preparations, I think that, with a bit of practice, parasitologists can learn to correlate these 2-D section to our familiar 3-D objects , given that D. caninum is the only parasite in humans to produce these characteristic egg packets.  Thank you all for writing in!

And now a poem from Blaine Mathison:

A baby cuddling with a kitten is such a cute scene

Until the kid accidentally swallows an infected cat flea

For down in his intestines a new pet does come

For he’s host to the cestode Dipylidium caninum 

shedding motile proglottids in the kid’s soiled Onesie

Case of the Week 319

This week's case is also generously donated by Florida Fan, who has just had a run of really great cases!  The specimen is a particularly striking trichrome-stained stool specimen from a 20 year-old male from Florida (1000x):

Identification?

Answer to Case 319

Answer:  Giardia duodenalis (a.k.a. G. lamblia, G. intestinalis) trophozoites.

This was a very impressive case given the large number of trophozoites present. Tomáš Macháček asked how often this number of trophozoites is 
found in stool compared with cysts. In my experience (and in the 
experience of the Florida Fan who donated this case), this amount 
of trophozoites is very uncommon - typically seen only in duodenal 
aspirates.

Case of the Week 318

This week's case was generously donated by Florida Fan.  The following objects were seen in iodine-stained stool concentrates:

(450x)

(1000x)

The identification was confirmed using a Modified Safranin method:





Identification?

Answer to Case 318

Answer:  Cryptosporidium species.

The small size of these spherical structures (4-6 micrometers in diameter) and bright red staining using the Modified Safranin stain (which is similar to a modified acid fast stain) is characteristic for this species.  Arthur Morris mentions that the differential would be the similar-appearing oocysts of Cyclospora, but that these can be excluded because they would be larger and also typically have a 'broken glass' internal appearance. 

One reader commented that this could be C. parvum or C. hominis, the 2 most common species found in humans.  However, there are a number of other species that may be less commonly found in humans, and it is not possible to tell the different species apart by morphology alone.

Thanks again to Florida Fan for this case!

Also, Blaine wanted to let us know that he hasn't forgotten about us, and created the following poem during his 'free time' between the numerous workshops that the CDC DPDx group is putting on:

No poems from Blaine, where did he go?

He’s just been too darn busy don’t you know.

As soon as we’re caught up

And our workshops are done

You’ll be treated to some parasitological poetry fun.

Case of the Week 317

The following was seen on a Pap-stained endocervical smear.  Identification?

Thanks to Dr. Audrey Schuetz who donated this case!

Answer to Case 317

Answer:  Not a Parasite; most consistent with a fiber containing proteinaceous deposits.  One reader suggested obtaining additional information such as whether the patient was using an IUD or tampon.  We can say with confidence that it is not a fungus or other microorganism.

Thank you all for writing in.  I think that everyone recognized this as a non-parasite, and it was very interesting to hear the different hypotheses on what it actually is.