Monday, September 20, 2021

Case of the Week 654

 This week's case is of a middle-aged man with a painful lesion on the dorsum of his foot. He recently returned from Brazil, during which he swam in the ocean, walked barefoot on the beach, and ate local foods. An excisional biopsy was performed and submitted to the clinical microbiology lab to rule out a possible parasite. The specimen received was an excised ellipse of skin on which there was a central defect measuring ~ 5 mm in diameter:

There was also a separate section of subcutaneous tissue, which contained numerous tan-white ovoid objects:
Here is a close-up of these objects:
To confirm our suspected diagnosis, we serially sectioned the skin and submitted the sections for histopathologic processing. Here are a couple of images from the H&E stained slides (using the 4x and 10x objectives):


Identification?


Monday, September 13, 2021

Case of the Week 653

 This week's case was generously donated by Drs. Alex Fenwick and Julie Ribes at the University of Kentucky. The following structure was retrieved from bronchial washings of a patient with end-stage lung disease due to cystic fibrosis.  

The next 2 images show both ends of this object.

Most likely identification?


Sunday, September 12, 2021

Answer to Case 653

 Answer to the Parasite Case of the Week 653: Not a human parasite; most likely a mucus cast.

As noted by Florida Fan, "The object did not have any internal organization nor visible external anatomy. It displays a ribbon like morphology being flat and slender especially at the bend." 

Sam had a similar thought and suggested that since the "patient had cystic fibrosis it may be some kind of mucous plug."  

To test these hypotheses, we can gently manipulate the object. Mucus usually separates easily whereas a true nematode has a firm, rubbery cuticle and is harder to tear. As CA noted, although not a first choice, we could also put a section through for histopathology. Histopathologic examination can be extremely helpful in several instances, such as when looking for the characteristic lateral cords of the anisakids (see Case of the Week 177) or the uterine branches of Taenia spp. proglottids (See Case of the Week 361).

Thanks again to Drs. Ribes and Fenwick for donating this interesting case!

Monday, September 6, 2021

Case of the Week 652

Happy Labor Day weekend to my American readers! It's the first Monday of the month, and time for our monthly case from Idzi Potters and the Institute of Tropical Medicine, Antwerp. The following structures were seen in Ziehl-Neelsen stained sputum specimen for acid fast bacilli, thus prompting additional examination of direct wet mounts. The patient had recently from Sicily. 

Ziehl-Neelsen stained sputum specimen:


Direct wet mount:




Identification?

Sunday, September 5, 2021

Answer to Case 652

 Answer to the Parasite Case of the Week 652: Strongyloides stercoralis L3 (filariform) larvae.

As nicely described by Luis, "We can see in photo 2 an esophagus almost as long as the intestine, the tail is sharp and has notches (photo 3)."

The notches are classic and can be seen in both the the Ziehl-Neelsen (ZN) stained preparation and wet prep (inset), (arrows). 

The ZN stain had been performed to screen for acid fast bacilli (AFB). AFBs would stain bright red with the carbol fuchsin dye, whereas the larva is only stained here with the methylene blue counter stain. 

This case goes well with last week's, in which we saw L1 (rhabditiform) larvae of S. stercoralis

Thanks again to Idzi for donating this great case!