(Unstained, 100x original magnification)
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(Unstained, 200x original magnification)
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(Unstained, 200x original magnification)
Monday, February 22, 2010
Case of the Week 106
The follow are images of an unstained intestinal biopsy that was "squashed" between 2 slides. Please identify the objects present. They measure approximately 180 microns in greatest dimension. (CLICK ON IMAGES TO ENLARGE)
(Unstained, 100x original magnification)
.jpg)
(Unstained, 200x original magnification)
.jpg)
(Unstained, 200x original magnification)
(Unstained, 100x original magnification)
(Unstained, 200x original magnification)
(Unstained, 200x original magnification)
Sunday, February 21, 2010
Answer to Case 106
Answer: Schistosoma mansoni eggs
This case seemed to generate a lot of enthusiasm from the audience. Thank you all for the great comments! The eggs shown here are classic for S. mansoni, with their large size (>150 microns largest dimension) and classic lateral spine.
Chris C. asked how I thought to do the squash preparation on this tissue. The answer is that this tissue was submitted specifically to look for Schistosoma eggs. As you can imagine, this is a rare request when you practice in an area that does not have endemic schistosomiasis. However, we do on occasion receive rectal biopsies in microbiology for this technique. It's important that the tissue be sent fresh, since fixed tissue will not squash easily, and does not provide a good preparation.
If tissue has already been placed in formalin, then it is best to submit it to surgical pathology. Unfortunately, you then get a lot of fixation artifacts, and the eggs become very distorted, as seen below:
By looking carefully, you still may be able to find a lateral spine. But be careful about calling 'spines' when all you are seeing are collapsed, angulated eggs. You'll want to be sure that you are seeing a well defined spine in the expected position. Here is a really good example of a lateral spine that survived fixation, dehydration, and sectioning:
This case seemed to generate a lot of enthusiasm from the audience. Thank you all for the great comments! The eggs shown here are classic for S. mansoni, with their large size (>150 microns largest dimension) and classic lateral spine.
Chris C. asked how I thought to do the squash preparation on this tissue. The answer is that this tissue was submitted specifically to look for Schistosoma eggs. As you can imagine, this is a rare request when you practice in an area that does not have endemic schistosomiasis. However, we do on occasion receive rectal biopsies in microbiology for this technique. It's important that the tissue be sent fresh, since fixed tissue will not squash easily, and does not provide a good preparation.
If tissue has already been placed in formalin, then it is best to submit it to surgical pathology. Unfortunately, you then get a lot of fixation artifacts, and the eggs become very distorted, as seen below:
By looking carefully, you still may be able to find a lateral spine. But be careful about calling 'spines' when all you are seeing are collapsed, angulated eggs. You'll want to be sure that you are seeing a well defined spine in the expected position. Here is a really good example of a lateral spine that survived fixation, dehydration, and sectioning:
Monday, February 15, 2010
Case of the Week 105
Here is a special case in honor of Valentines day. The following section of lung was removed due to the presence of a nodule that mimicked a lung carcinoma. However, on sectioning and H&E staining, the following was seen. Identification?
Bonus question - what does this case have to do with Valentines day???
Bonus question - what does this case have to do with Valentines day???
Sunday, February 14, 2010
Answer to Case 105
Answer: Dirofilaria immitis; the Dog Heartworm
Congratulations to everyone who wrote in with the correct answer to this case!
Dirofilaria spp. cause both subcutaneous and pulmonary infections in humans, with D. immitis being largely responsible for the pulmonary infections in the U.S. and worldwide. In dogs, the adult worms live in the right side of the heart and cause debilitating disease. The adults produce unsheathed larvae which circulate in the blood and are transmitted to other hosts through the bite of an infected mosquito. Humans are accidental hosts that also acquire infection through a mosquito bite. However, the worms cannot live in the human heart and quickly die and are passively transported to the lungs where they wedge in a small vessel and produce an infarct. Eventually the lesion heals as a granulomatous coin lesion which can mimic a primary or metastatic tumor. It's easy to forget that there is filarial disease in the U.S.!
On resection, the worms are found in various stages of degeneration with a surrounding inflammatory response. They can be recognized by their size (150 - 300 microns in diameter) and thick multi-layered cuticle with lateral internal cuticular ridges (arrows, image below). The internal organs degenerate quickly and are more difficult to identify.
To demonstrate the variable appearance of Dirofilaria spp. in tissue, here a number of other images from different cases. The appearance of the internal structures are variable, but note the internal cuticular ridges in all cases.
Most of you realized the Valentine's Day connection with the Heart worm. Maybe next year I'll be able to find a fun heart-shaped cross-section of a worm for you.
Thank you for writing in and leaving your comments!
Congratulations to everyone who wrote in with the correct answer to this case!
Dirofilaria spp. cause both subcutaneous and pulmonary infections in humans, with D. immitis being largely responsible for the pulmonary infections in the U.S. and worldwide. In dogs, the adult worms live in the right side of the heart and cause debilitating disease. The adults produce unsheathed larvae which circulate in the blood and are transmitted to other hosts through the bite of an infected mosquito. Humans are accidental hosts that also acquire infection through a mosquito bite. However, the worms cannot live in the human heart and quickly die and are passively transported to the lungs where they wedge in a small vessel and produce an infarct. Eventually the lesion heals as a granulomatous coin lesion which can mimic a primary or metastatic tumor. It's easy to forget that there is filarial disease in the U.S.!
On resection, the worms are found in various stages of degeneration with a surrounding inflammatory response. They can be recognized by their size (150 - 300 microns in diameter) and thick multi-layered cuticle with lateral internal cuticular ridges (arrows, image below). The internal organs degenerate quickly and are more difficult to identify.
To demonstrate the variable appearance of Dirofilaria spp. in tissue, here a number of other images from different cases. The appearance of the internal structures are variable, but note the internal cuticular ridges in all cases.
Most of you realized the Valentine's Day connection with the Heart worm. Maybe next year I'll be able to find a fun heart-shaped cross-section of a worm for you.
Thank you for writing in and leaving your comments!
Monday, February 1, 2010
Case of the week 104
The following H&E stained histologic sections are from a rectal abscess in a 5 year old boy. Identification? (CLICK ON IMAGES TO ENLARGE)
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Answer to Case 104
Answer: Pinworm (Enterobius vermicularis eggs.
A few of you noticed that I gave the answer away on the close up image! Thanks for writing in to let me know and share your thoughts.
As you all probably know, this is an extremely rare presentation of pinworm infection. Typically, deposition of eggs by the female work in the perianal skin folds causes intense itching. It is only when the worm and/or eggs ends up in a place where they shouldn't be (e.g. genital tract, colon diverticulum or fissure) that an abscess can form, and complications arise, such as seen in this case.
The diagnosis is made by identifying the characteristic eggs, measuring approximately 50-60 microns in greatest dimension.
Salbrent had asked: "Can you tell if this is recent infection or an older one?"
I believe this manifestation (the abscess) is acute, since the inflammatory response consists of neutrophils, and there is no evidence of granulation tissue or fibrosis. As far as the infection itself however, I'm not sure if it's possible to say how long it's been going on. The adult worms only live for a few months, but autoinfection is common, so it's possible that the infection has been around longer than a few months.
A few of you noticed that I gave the answer away on the close up image! Thanks for writing in to let me know and share your thoughts.
As you all probably know, this is an extremely rare presentation of pinworm infection. Typically, deposition of eggs by the female work in the perianal skin folds causes intense itching. It is only when the worm and/or eggs ends up in a place where they shouldn't be (e.g. genital tract, colon diverticulum or fissure) that an abscess can form, and complications arise, such as seen in this case.
The diagnosis is made by identifying the characteristic eggs, measuring approximately 50-60 microns in greatest dimension.
Salbrent had asked: "Can you tell if this is recent infection or an older one?"
I believe this manifestation (the abscess) is acute, since the inflammatory response consists of neutrophils, and there is no evidence of granulation tissue or fibrosis. As far as the infection itself however, I'm not sure if it's possible to say how long it's been going on. The adult worms only live for a few months, but autoinfection is common, so it's possible that the infection has been around longer than a few months.
Monday, January 25, 2010
Case of the Week 103
The following peripheral blood film was obtained from a patient living in Missouri. Besides being an outdoorsman, he had traveled extensively in the past year, and visited many parts of Africa and Asia.
Diagnosis?
Diagnosis?
Sunday, January 24, 2010
Answer to Case 103
Answer: Babesia spp. As I noted previously, this patient was from Missouri, and was found to have the newly described MO-1 strain. Notice the multiply infected RBCs and atypical forms which are characteristic for infection with Babesia spp. Several viewers suggested Plasmodium falciparum as an alternative. This is definitely in the differential diagnosis, since they can both demonstrate high parasitemia, multiply infected RBCs, and small delicate rings on peripheral blood smear. Also, intermediate stages (e.g. schizonts) are almost never seen in P. falciparum infection, and never seen in Babesia infection. This overlap in morphologic features can create quite a challenge in distinguishing the 2 infections.
However, babesiosis can be distinguished from malaria (P. falciparum infection) by the following features:
1. Babesia has frequent extra-cellular forms.
2. Size variability of ring-forms is often marked.
3. Rings are often atypical, and include spindle, oval, round, and double rings forms. I've also noticed a high frequency of "tennis racket-shaped" rings, where a "handle" is present on the ring.
4. Finally, the rarely seen tetrad, or maltese cross, is diagnostic of babesiosis. This was also seen in this case, but I had excluded this image originally so I wouldn't give the answer away immediately!
Despite the newly describes Babesia variants, the most commonly reported species in the United States is stillBabesia microti.
However, babesiosis can be distinguished from malaria (P. falciparum infection) by the following features:
1. Babesia has frequent extra-cellular forms.
2. Size variability of ring-forms is often marked.
3. Rings are often atypical, and include spindle, oval, round, and double rings forms. I've also noticed a high frequency of "tennis racket-shaped" rings, where a "handle" is present on the ring.
4. Finally, the rarely seen tetrad, or maltese cross, is diagnostic of babesiosis. This was also seen in this case, but I had excluded this image originally so I wouldn't give the answer away immediately!
Despite the newly describes Babesia variants, the most commonly reported species in the United States is stillBabesia microti.
Monday, January 18, 2010
Case of the Week 102
A patient with recurrent high grade lymphoma on an extensive chemotherapeutic regimen presented with increasing shortness of breath and consolidation on chest radiograph. Antibiotic therapy was unsuccessful and she expired. Autopsy of the lungs showed the following on hematoxylin and eosin staining (CLICK ON IMAGES TO ENLARGE):
(10x objective, 100x final magnification)
(40x objective, 200x final magnification)
(100x objective, oil immersion, 1000x final magnification)
(100x objective, oil immersion, 1000x final magnification)
(100x objective, oil immersion, 1000x final magnification)
Diagnosis of this unfortunate case?
(10x objective, 100x final magnification)
(40x objective, 200x final magnification)
(100x objective, oil immersion, 1000x final magnification)
(100x objective, oil immersion, 1000x final magnification)
(100x objective, oil immersion, 1000x final magnification)
Diagnosis of this unfortunate case?
Sunday, January 17, 2010
Answer to Case 102
Answer: Amebic pneumonia; most likely due to Acanthamoeba spp. or Balamuthia mandrillaris.
This is a rare manifestation of disease with the free-living amebae. More commonly, Acanthamoeba spp. cause amebic keratitis - typically in contact lens wearers. However, this organism and B. mandrillaris can rarely gain access to the systemic circulation of immunocompromised (and occasionally immunocompetent) individuals and travel to the brain, where it causes granulomatous amebic encephalitis. The lungs and skin are thought to be primary sites of entry into the body.
These amebae can be differentiated from Entamoeba histolytica by the presence of a large karyosome and cysts in tissue. In comparison, E. histolytica has a small central karyosome with uneven rim of clumped chromatin, and it does not form cysts in tissue.
Thanks to everyone who took a chance and wrote in on this challenging case!
This is a rare manifestation of disease with the free-living amebae. More commonly, Acanthamoeba spp. cause amebic keratitis - typically in contact lens wearers. However, this organism and B. mandrillaris can rarely gain access to the systemic circulation of immunocompromised (and occasionally immunocompetent) individuals and travel to the brain, where it causes granulomatous amebic encephalitis. The lungs and skin are thought to be primary sites of entry into the body.
These amebae can be differentiated from Entamoeba histolytica by the presence of a large karyosome and cysts in tissue. In comparison, E. histolytica has a small central karyosome with uneven rim of clumped chromatin, and it does not form cysts in tissue.
Thanks to everyone who took a chance and wrote in on this challenging case!
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