Monday, March 1, 2021

Case of the Week 628

 This week's case is from Idzi Potters and the Institute of Tropical Medicine, Antwerp. It looks somewhat similar to last week's case, but it is very different! 

The following objects were seen in a stool specimen from a middle-aged male with recent travel to Senegal.


Monday, February 22, 2021

Case of the Week 627

This week's interesting case was donated by Dr. Karine Thievierge and Alexandra. The following structures were seen in a stool specimen. They measure between 110 - 140 micrometers in length, by 75 - 90 micrometers in width.  Identification?

Sunday, February 21, 2021

Answer to Case 627

 Answer to the Parasite Case of the Week 627: Mite eggs; finding is not of medical concern

Mites and their eggs may occasionally be found in human stool specimens, given that mites are all around us - in dust, on our skin, and in our food! (check out my previous case of the week on Cheese Mites). Although mite eggs resemble those of some human parasites (e.g., the human hookworms), they are usually larger, and there is often evidence of an immature mite inside, as seen in this case:

Here are a couple of images from Dr. Jon Rosenblatt, my predecessor at Mayo Clinic. They show 2 larval mites, including one escaping from an egg. 

Live, moving, mites can occasionally be seen in direct wet preps of fresh stool - a somewhat disconcerting but insignificant finding. We don't report them when seen as it would just cause confusion for the ordering provider and patient!

Monday, February 15, 2021

Case of the Week 626

 This week's post is from my own collection - A Giemsa-stained preparation of vaginal secretions from a woman with dyspareunia. The objects measure approximately 15-20 micrometers in maximum dimension. 


On a related topic, I had the privilege of recording a podcast with Dennis Strenk, the founder and voice of the People of Pathology Podcast. You can listen to our podcast here:






Sunday, February 14, 2021

Answer to Case 626

 Answer to the Parasite Case of the Week 626: Trichomonas vaginalis. The images from this case show the classic morphology of this organism. Here are some of these key diagnostic features:

Although T. vaginalis can be seen in vaginal secretions, male urethral secretions, and in urine, the most sensitive detection method is a nucleic acid amplification test (NAAT). This is what we use in my laboratory. Importantly, the NAAT we use does not cross-react with the other trichomonads found in the oral cavity and intestine. 

As Sam mentioned, "Treatment with metronidazole would be appropriate. This would be of concern if the patient was pregnant as T. vaginalis can cause premature rupture of membranes, preterm birth, and decreased birth weights." T. vaginalis can also increase the risk of HIV transmission, so treatment is indicated even if the patient is asymptomatic.

Thanks to all who wrote in with comments!

Monday, February 8, 2021

Case of the Week 625

 This week's case was generously donated by Dr. Marijo Roiko, Dr. Shifteh Vahidi, and Ms. Marnie Larsen. Marnie noticed the unusual structure shown in the image below in a urine cytology specimen from an elderly male with a history of hematuria. The structure in the image was observed on PAP stain and was a solitary finding; it measures 125 x 75 ┬Ám.


What is this cool-looking object?

Sunday, February 7, 2021

Answer to Case 625

Answer to the Parasite Case of the Week 625: Not a parasite; rotifer

This fascinating "wheel animal" (from Latin rota "wheel" and -fer "bearing") has been seen a couple of times in the past on this blog. Check out our previous cases with great photos and videos:

Case 517 (unstained with video)

Case 304 (another Pap-stained case)

Here are some of the diagnostic features in this case:

Old one gives us a great description of the rotifer seen here: "Bdelloid rotifer with a retracted corona, large orange ovary, with 2 lateral germovitellaria with posterior stomach. Tail section appears to be visibly segmented with one of its toes visible at the terminal segment."

As I've noted in my previous posts, there is no clinical significance to this finding. Rotifers are found in environmental water sources, so it is likely that the organism entered the specimen through the collection process - possibly from a toilet using untreated well water.

Some of you suggested that this could be a miracidium of Schistosoma haematobium. While this is a good thought given the size and location, we can exclude this organism based on the overall shape of the organism, lack of circumferential cilia, and presence of a segmented foot (retracted, but still visible)..

Thanks again from our colleagues at Altru Health System for donating this fun case!

Monday, January 25, 2021

Case of the Week 624

 This week's case is a bit unusual in that it is an environmental sample (but the parasite has relevance to human health). The following were seen in a soil sample taken from a child's playground. They are approximately 80 micrometers in greatest dimension. Most likely identification?

Sunday, January 24, 2021

Answer to Case 624

 Answer to the Parasite Case of the Week 624: Toxocara sp. eggs. Note that one is fully embryonated and contains an L3 larva. These eggs are found in the feces of the definitive hosts: T. canis in canids and T. cati in felids. Based on the size, the eggs in this case of likely to be those of T. canis, which is slightly small than the eggs of T. cati (80-85 vs 65-75 microns respectively). Of note, these eggs are NOT found in human feces. However, they are a risk to humans if ingested, since eggs with larvae will hatch and can cause visceral larva migrans. That is why finding eggs in the soil of a child's playground is particularly concerning. 

The eggs can be identified by their thick outer shell with a pitted surface. It's a very striking appearance. 

You can read more about these fascinating zoonotic parasites on the U.S. Centers for Disease Control and Prevention (CDC) DPDx website. Toxocariasis is identified by the CDC as one of 5 Neglected Parasitic Infections in the United States, and is quite prevalent in many places worldwide. 

Tuesday, January 19, 2021

Case of the Week 623

 The following objects were seen on a peripheral blood film from a patient with chronic, worsening swelling in his groin over the past 5 years. He is from Central Africa. The stain is the Delafield's hematoxylin. Diagnosis?