Monday, May 29, 2017

Case of the Week 447

This week's case is in honor of Memorial Day and was generously donated by Florida Fan. I've actually revived this from a previous case, since the colors (red, white and blue) are so beautiful with Florida Fan's rendition of the modified safranin stain. The red objects seen below were found in stool and measure approximately 10 micrometers in diameter.


Monday, May 15, 2017

Case of the Week 446

This week's very timely case was donated by George at Memorial Sloan Kettering Cancer Center. The following objects were seen in a wet mount of a concentrated stool specimen. They measure less than 20 micrometers in dimension and do not have an apparent operculum.

Here is their appearance using iodine:


Sunday, May 14, 2017

Answer to Case 446

Answer: not a parasite; most consistent with mushroom spores.

In this case, the spores were noted in the stool of an individual who had consumed morel mushroom spores, and therefore we can be more specific about the identification.

Mushroom spores are a convincing mimic of parasite eggs. They can be differentiated by a few features, however:
1. Their size is smaller than Enterobius vermicularis eggs - one of their closest mimics.
2. Although in the size range for some of the smaller trematode eggs (e.g. Clonorchis, Metagonimus), they lack an operculum.

Again, special thanks to George who donated these images and reminded me that it is now morel mushroom season!

Monday, May 8, 2017

Case of the Week 445

This week's amazing case was donated by Mr. Boren Huot. This object was seen in a stool specimens from a patient in Cambodia.  Identification? (CLICK ON THE IMAGES TO ENLARGE)

Sunday, May 7, 2017

Answer to Case 445

Answer: Capillaria philippinensis

This case shows an adult worm containing characteristic eggs of C. philippinensis. Note that each egg has a striated wall and bipolar plugs.
Thanks to the CDC DPDx for the photo of the egg shown in the upper right hand corner of the above image.

One reader asked how you could tell C. philippinensis apart from C. hepatica, since both can infect humans. The biggest clue in this case is that the worm was found in stool, whereas the adult worms of C. hepatica are only found in the liver. There are also subtle features of the adult worm and eggs that allow the 2 species to be differentiated.

Thanks again to Mr. Huot for donating a case that we don't get to see very often in the United States.

Friday, April 28, 2017

Case of the Week 444

The week's case was generously donated by Dr. Julie Ribes. The following material was obtained from an ostomy bag.


Thursday, April 27, 2017

Answer to Case 444

Answer: not a parasite; most consistent with banana seeds.

This is something that we commonly see in my lab, and I've previously featured other examples of banana seeds on this blog. Here are the links to 2 previous posts:
Case 139
Case 402

Because I've received some degree of skepticism when I've posted banana seeds in the past, I decided to conduct an experiment to see if I could recreate their appearance through some laboratory digestion techniques. So here was my process:

Step 1. Sacrifice my banana from lunch for the good of science

Note the small immature seeds that are seen in these longitudinal sections. A fun fact - the bananas that we buy in the grocery store have been bred so that the seeds never mature. Wild bananas have large seeds which make the fruit less pleasant to eat.

Step 2. Add bananas to pre-prepared tubes of proteinase K in buffer. (Unfortunately I didn't have any amylase which would have digested the carbohydrates in the banana. However, this was the best I could do to simulate the digestive process). Vortex to mix and then incubate at 56 degrees Celsius while gently shaking (the standard tissue digestion that we use for PCR pre-processing).

Step 3. Check regularly. I first checked every 10 minutes , but very quickly realized that this was going to be a long process. After the first 4 hours, this is how the banana sections looked:

Step 4. Check again, 24 hours later - looking pretty good!
Step 5. Final check - 48 hours. Success! I think that these look nearly identical to our clinical specimen. What do you think?
Close-up view of the seeds (look a lot like the previous cases):

Again, it's not a perfect match since the actual patient specimen was subjected to the entire gastrointestinal digestive process. However, the strings of immature seeds can clearly be seen. Here is how they look microscopically:
You can also appreciate the starch granules of the banana (taken using a 40x and 100x objective):

I hope you all enjoyed this experiment as much as I did!

Sunday, April 23, 2017

Case of the Week 443

This week's case was donated by Dr. Tom Grys. The patient is an immunocompromised man with hemophagocytic lymphohistiocytosis (HLH) and fever. He reports travel throughout the United States and Italy. Bone marrow biopsy revealed the following:


Saturday, April 22, 2017

Answer to Case 443

Answer: Leishmania amastigotes
This case shows the characteristic morphology of amastigotes within a macrophage. The arrow below highlights an amastigote in which the nucleus and kinetoplast can both be seen.
One of the most important teaching points about this case is that the patient acquired infection in Italy - a country that many physicians (especially in the United States) do not realize is endemic for Leishmania infantum. Of note, Leishmania infantum is nearly identical to L. chagasi, a pathogen found in the Americas, and some consider them to be the same organism (in which case L. infantum would have preference).

Sunday, April 16, 2017

Case of the Week 442

This week's case was generously donated by Dr. Bryan Schmitt and Kayla Kirby. The patient is a middle-aged man from West Africa who presented with a chief complaint of worms in his stool. Four tan-white objects were received in saline and an egg was expressed from one of them.