This week's case was generously donated from Drs. Cynthia Magro and Lars Westblade. The following object was identified in an hematoxylin and eosin stained tissue section of toenail in a patient with onychomycosis. Identification?
Monday, May 3, 2021
Welcome back to the first Monday of the month! It's time for our monthly case from Idzi Potters and the Institute of Tropical Medicine in Antwerp. The following structures were found in a stool specimen from a patient originally from the Democratic Republic of the Congo. He presented with long standing diarrhea (occasionally bloody), intermittent abdominal pain, decreased appetite and unintentional weight loss. They are approximately 200 micrometers long.
What is the most likely identification?
Sunday, May 2, 2021
Answer to Parasite Case of the Week 637: Schistosoma intercalatum
This was definitely a tricky case! The eggs strongly resemble those of Schistosoma haematobium, but stool would be an unusual source for this parasite, and the eggs in this case are larger than what would be expected for S. haematobium (usual size is 110 to 170 micrometers long). In comparison, S. intercalatum eggs are most often found in stool and measure 140 to 240 micrometers long. They also characteristically have an equatorial bulge as seen in one of the images from this case:
Of note, Schistosoma intercalatum has a very limited geographic distribution, being found primarily in the Congo area. Therefore, getting a travel history can be extremely helpful. As Marc Couturier pointed out on Twitter, the other major consideration is S. guineensis due to the morphologic similarities of the eggs of the two species. If a location had not been provided, then reporting out "Schistosoma intercalatum/S. guineensis" would be best.
Monday, April 26, 2021
This week's case was donated by one of our intrepid infectious diseases fellows, Dr. Geno Tai, who was travelling across country and found these arthropods in his lodging. Identification? Photos and video courtesy of his friend and travel-mate, Dr. Chris Hwang.
Sunday, April 25, 2021
Answer to the Parasite Case of the Week 636: Cimex sp.
Given the location (hotel in North America), this is most likely Cimex lectularis, the common bed bug. However, we would want to have a closer examination to be sure. It looks like we have a couple of different life cycle stages here. Also, at least one squished well-fed one - nice job Geno!
Here is a good resource for information.
Monday, April 19, 2021
This week's case features a fun finding in a concentrated wet prep of stool stained with iodine. The case and photograph are from Blaine Mathison and Madison Sant. The object below measures approximately 35 micrometers in diameter. Identification?
Sunday, April 18, 2021
Answer: Entamoeba coli, supernucleate cyst. Typical E. coli cysts have 8 nuclei, but I'm counting at least 18 nuclei in this one. My first thought when I saw this photograph was - holy moly E. coli! Thanks again to Blaine and Madison for donating this fun case.
Monday, April 12, 2021
Sunday, April 11, 2021
Answer to Parasite Case of the Week 634: Free-living mite, likely contaminant during specimen collection/preparation.
Note the 8 legs (consistent with a member of the arachnidae) and the long spines (setae). It is easier to appreciate all 8 legs by carefully watching the video in this case.
As noted by Marc Couturier, "I mite have to say this is a contamination of the preparation and not coming from stool." I agree with this assessment! While this mite could have been ingested from a food source (e.g., mimolette cheese; see my previous post), I find it highly unlikely that the mite would still be alive and active after passing through the intestinal tract. I also find the presence of squamous epithelial cells nearby to be rather suspicious for environmental contamination.
Thanks again to Dr. José Poloni for donating this interesting case, and to all of the readers who wrote in with their helpful commentary.
Monday, April 5, 2021
This week's case was generously donated by Dr. Neil Anderson. The following structure was retrieved from the common bile duct during endoscopic retrograde cholangiopancreatography (ERCP). The patient is a refugee from Tanzania who presented with intermittent abdominal pain, distended gallbladder and hepatosplenomegaly. This was one of many "worm like" structures noted on ERCP. Unfortunately this object appeared to tear during removal. The portion submitted measures several centimeters in length. No identifying external structures were identified.
Dr. Anderson's team tried to express eggs from this structure but was unsuccessful. In an effort to learn more about the nature of this object, a portion of it was submitted for histopathologic processing. Representative sections revealed the following:
What is the most likely identification?