H&E, 20x
Tuesday, June 16, 2015
Case of the Week 353
This week's case was generously donated by Bryan Schmitt and Stephanie Kinney at Indiana University. Several specimens measuring approximately 1 cm in length were obtained during routine colonoscopy on a hispanic woman in her 50's; they were mistaken as colon polyps and submitted for histopathology. Identification?
H&E, 20x
H&E, 400x
H&E, 20x
Sunday, June 14, 2015
Answer to Case 353
Answer: Taenia saginata proglottid
There are several key morphologic features that allow for identification of this specimen. First, the presence of loose, 'myxoid' stroma, thick acellular cuticle and calcareous corpuscles allow for general identification as a cestode; in this case, a proglottid.
Next, identification of the small eggs with radial striations allow for further confirmation that this is a cestode, and identification to the Taenia genus.
Finally, the species can be tentatively identified as T. saginata, based on the presence of >13 primary branches (arrow heads) off of the central uterine stem (arrow).
Florida Fan noted that T. asiatica also has > 13 primary uterine branches and is essentially indistinguishable from T. saginata. However, Arthur rightly mentions that T. asiatica has not been described outside of Asia, presumably due to somewhat unique culinary habits of some Asian populations that include consumption of raw pig liver. Given that this patient was from Central America, she likely did not have exposure to T. asiatica, although we would need to perform molecular testing on the specimen to definitely rule out this species.
There are several key morphologic features that allow for identification of this specimen. First, the presence of loose, 'myxoid' stroma, thick acellular cuticle and calcareous corpuscles allow for general identification as a cestode; in this case, a proglottid.
Next, identification of the small eggs with radial striations allow for further confirmation that this is a cestode, and identification to the Taenia genus.
Finally, the species can be tentatively identified as T. saginata, based on the presence of >13 primary branches (arrow heads) off of the central uterine stem (arrow).
Florida Fan noted that T. asiatica also has > 13 primary uterine branches and is essentially indistinguishable from T. saginata. However, Arthur rightly mentions that T. asiatica has not been described outside of Asia, presumably due to somewhat unique culinary habits of some Asian populations that include consumption of raw pig liver. Given that this patient was from Central America, she likely did not have exposure to T. asiatica, although we would need to perform molecular testing on the specimen to definitely rule out this species.
Sunday, June 7, 2015
Case of the Week 352
The following structures were seen in a hematoxylin and eosin-stained perianal skin biopsy from an Ethiopian man with recurrent colorectal fistulae and abscesses. Presumptive identification? What study would you recommend to confirm your diagnosis?
100x total magnification
400x total magnification
100x total magnification
200x total magnification
400x total magnification
Saturday, June 6, 2015
Answer to Case 352
Answer: Schistosoma sp. ova; most likely S. mansoni
As the readers pointed out, the appearance of eggs within granulomas in a perianal skin biopsy is highly suggestive of schistosomiasis, and image 4 might have the beginning of a lateral spine to support the diagnosis of S. mansoni infection. Unfortunately, the eggs tend to collapse in tissue sections and therefore it is difficult to definitively identify the characteristic spines. A stool examination is recommended to confirm the identification of these eggs. In this case, the O&P confirmed that this was S. mansoni infection.
Thank you all for writing in!
As the readers pointed out, the appearance of eggs within granulomas in a perianal skin biopsy is highly suggestive of schistosomiasis, and image 4 might have the beginning of a lateral spine to support the diagnosis of S. mansoni infection. Unfortunately, the eggs tend to collapse in tissue sections and therefore it is difficult to definitively identify the characteristic spines. A stool examination is recommended to confirm the identification of these eggs. In this case, the O&P confirmed that this was S. mansoni infection.
Thank you all for writing in!
Monday, June 1, 2015
Case of the Week 351
Greetings from the New Orleans, the site of the 2015 ASM general meeting! This week's case is a conventional endocervical smear stained with Papanicolaou stain. The images are taken at 400x total magnification, with the orange-staining structures measuring approximately 60 micrometers in length.
Identification?
Identification?
Sunday, May 31, 2015
Answer to Case 351
Answer: Enterobius vermicularis (pinworm) eggs
Pinworm eggs measure approximately 60 micrometers in length and have a classic asymmetric oval shape with flattening on one side. They usually take on a striking deep orange color on Pap stain.
The eggs are fully infectious within 4-6 hours of being laid, so it is not uncommon to see a folded larva within the egg.
As mentioned by Kevin and Prasad, these eggs may have been introduced via contamination from the perianal area or could represent an ectopic pinworm infection involving the genital tract. In either scenario, clinical investigation and treatment are indicated.
Pinworm eggs measure approximately 60 micrometers in length and have a classic asymmetric oval shape with flattening on one side. They usually take on a striking deep orange color on Pap stain.
The eggs are fully infectious within 4-6 hours of being laid, so it is not uncommon to see a folded larva within the egg.
As mentioned by Kevin and Prasad, these eggs may have been introduced via contamination from the perianal area or could represent an ectopic pinworm infection involving the genital tract. In either scenario, clinical investigation and treatment are indicated.
Monday, May 25, 2015
Case of the Week 350
This week's case is in honor of the Live Global Health Course sponsored by the University of Minnesota, in collaboration with the Centers for Disease Control and Prevention. I have the honor of teaching the Entomology lab tomorrow along with Blaine Mathison, and therefore thought I would choose an entomology case for you this week. This week's case was generously donated by Florida Fan.
The patient is a young girl that had been diagnosed with seborrheic dermatitis. Scalp scrapings were submitted to the laboratory for fungal culture and smear and the following were seen:
Identification?
Sunday, May 24, 2015
Answer to Case 350
Answer: Pediculus humanus
Given the patient's history and location on the scalp, these arthropods are most likely P. h. capitis, a.k.a. head lice. As pointed out by Olivier and Lee, we have both a male and female louse here - a nice pair! You can identify the male by its terminal (caudal) projecting spike-like aedeagus (reproductive organ), while the female has a terminal inward-facing 'notch' representing the opening to the reproductive tract.
Given the patient's history and location on the scalp, these arthropods are most likely P. h. capitis, a.k.a. head lice. As pointed out by Olivier and Lee, we have both a male and female louse here - a nice pair! You can identify the male by its terminal (caudal) projecting spike-like aedeagus (reproductive organ), while the female has a terminal inward-facing 'notch' representing the opening to the reproductive tract.
Monday, May 11, 2015
Case of the Week 349
This week's case is a bit different in that I don't have an exact diagnosis for you. However, I have a general diagnosis and would actually like to get your opinion, dear readers, on what you think these structures are. The case was generously donated by Microbe Man. The photographs are H&E stained sections of appendix from child with acute appendicitis. The 4 objects measure 39, 46, 57 and 76 micrometers in greatest dimension and seem to be encased in a refractile shell.
200x
400x
600x
I will share with you next week how we signed this case out.
200x
I will share with you next week how we signed this case out.
Sunday, May 10, 2015
Answer to Case 349
Answer: Hairs, shown in cross-section
We believe that these structures are most likely hairs that have been ingested by the host (i.e. trichophagia) which could have potentially obstructed the appendix and resulted in appendicitis. I had not posted the answer until now because we were hoping to be able to prove the identity of these structure by staining them with keratin immunohistochemical stains and showing that they were refractile using polarized light (as we would expect to see with human hairs). Unfortunately we have not been able to get a hold of the slides again and therefore I will addend this post once we have conclusive evidence to share with you.
Thank you to everyone who wrote in to help with this case. We got a lot of great suggestions, with most readers agreeing that these structures were not parasites, but instead represented some type of foreign material. One astute reader also suggested that this could represent adiaspiromycosis, an infection by an aquatic protozoan parasite that can cause mass-like lesions of the nasal and ocular mucosa. Indeed, this case has a similar appearance but lacks the characteristic sporangia and sporangiospores. (You can see a case of adiaspiromycosis HERE).
We believe that these structures are most likely hairs that have been ingested by the host (i.e. trichophagia) which could have potentially obstructed the appendix and resulted in appendicitis. I had not posted the answer until now because we were hoping to be able to prove the identity of these structure by staining them with keratin immunohistochemical stains and showing that they were refractile using polarized light (as we would expect to see with human hairs). Unfortunately we have not been able to get a hold of the slides again and therefore I will addend this post once we have conclusive evidence to share with you.
Thank you to everyone who wrote in to help with this case. We got a lot of great suggestions, with most readers agreeing that these structures were not parasites, but instead represented some type of foreign material. One astute reader also suggested that this could represent adiaspiromycosis, an infection by an aquatic protozoan parasite that can cause mass-like lesions of the nasal and ocular mucosa. Indeed, this case has a similar appearance but lacks the characteristic sporangia and sporangiospores. (You can see a case of adiaspiromycosis HERE).
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