Molavi Chapter 3 - Inflammation Flashcards
Granulation tissue.
Note the loose, myxoid background with prominent fibroblasts and inflammatory cells. The capillaries are prominent and plump, with slightly more condensed stroma around them (giving them a pinkish halo)
Biopsy site changes
Indicates the site of a recent procedure. Characterized by fibroblast proliferation, foreign-body-type giant cells, suture material, foamy macrophages, fat necrosis, and inflammation.
Generally looks more solid than granulation tissue.
The arrow here points to foamy macrophages, which are ingesting the fat from the fat necrosis.
Types of giant cell
In-vivo example of Langerhans-type vs Foreign-body-type giant cells
Signals leading to formation of Langerhans-type, Foreign-body-type, and Touton-type giant cells
Langerhans-type: Typical of granulomas
Foreign-body-type: Part of foreign body reaction. Adhere directly to the foreign body.
Touton-type: Found in lesions containing cholesterol and lipid deposits. Associated with xanthomas and xanthogranulomas. The “foamy periphery” is due to fat droplets in the cytoplasm.
What is circled here?
A histiocyte / macrophage in tissue
Note the oval-shaped, grooved nucleus which is less consensed than the lymphocyte (arrow, for comparison)
They often are found together “swimming in a stream”
This one is tough.
It’s a hyalinized granuloma.
Sometimes old granulomas will hyalinize and become acellular. These rarely occur in the lung and can mimic neoplasia (pulmonary hyalinizin granulomas)
Stains for fungi
Pink on PAS stain
Black on Gomori’s methenamine silver stain (GMS)
This is taken from peripheral blood. On the left is giemsa-wright, on the bottom right is Gomori’s silver. What is the organism?
Histoplasma capsulatum
This is a lung biopsy taken from a very sick patient with cryptogenic pneumonia. The upper stain is an H and E, the lower stain is Gomori’s silver. What is the organism?
Pneumocystis jirovecii pneumonia
If you really want to rule out TB, you hvae to. . .
. . . scan the entire acid-fast slide at 40x power
It is painstaking, but necessary.
You spend an hour doing a painstaking 40x sweep of an acid-fast stain and don’t see any TB. But clinical suspicion remains high. What is the next best step?
Auramine-rhodamine stain.
It is more sensitive for TB, but is more expensive and requires a fluorescence microscope.
PAS stain in Whipple’s disease vs MAC
Whipple’s disease: Cranberry-stuffed macrophages
MAC: Rod-stuffed macrophages
Taken from a stomach biopsy. What is the diagnosis?
H. pylori.
The key to reading an H. pylori biopsy is to identify specifically in the areas of activity as seen on lower power, then zoom in to high power to look for these critters.
How would you interpret this biopsy if you saw it in a tonsil biopsy?
How about in someone with a jaw infection?
How about an endometrial biopsy?
That’s not fibrin! It’s a puffball colony, characteristic of actinomyces species.
If you saw this in a tonsil, it is probably just contamination by endogenous oral flora.
If it was part of a jaw infection, then your suspicion might be piqued that this could be actinomyces israelii infection.
If you saw it on an endometrial biopsy, this is actinomyces endometritis, a particularly nasty form of endometritis/pelvic inflammatory disease.
What’s going on in this ulcer biopsy?
This is a Herpesvirus infection (HSV-1 or HSV-2)
The classic appearance is a clump of fused cells with multiple molded nuclei and a peripheral chromatin rim and a large glassy inclusion (the viral proteins) in the middle.
“As though the chromatin is being digested from the inside out”
What’s going on in this ulcer biopsy?
This is cytomegalovirus.
The classic feature are enlarged cells with large nuclei carrying a characteristic dark oval inclusion surrounded by a pale halo (all within the nucleus!).
There will often also be a purple-reddish body of viral particles in the cytoplasm towards the edge of the cell. There may be fused cells as well, but typically not as extensively as in HSV.
What’s going on in this duodenal biopsy of an immunocompromised patient with diarrhea?
It almost looks like there are spores in the crypts.
Hence, cryptosporosis, hence, cryptosporidium.
What’s going on in this duodenal biopsy of a patient with diarrhea?
Giardia
Note the fish-like appearance of these organisms. They can look a lot like debris if you aren’t specifically looking for them. If you zoom in closer you might be able to see their classic Giardia whiskers.
