12. Systemic amyloidosis

Page created on November 22, 2018. Last updated on January 17, 2019 at 16:16

Organ: Kidney, liver, pancreas

Description:

The preparation contains slices of kidney (left), liver (centre), pancreas (right). All three organs have a greyish-whitish and have a rubber-like look.

Diagnosis: Systemic amyloidosis

Causes:

  • Systemic AL-type (primary amyloidosis)
    • Plasma cell tumour
  • Systemic AA-type (secondary amyloidosis)
    • Chronic inflammation
    • Inflammatory bowel disorders
    • Tuberculosis
    • Rheumatoid arthritis
    • Systemic lupus erythematosus

Theory:

Amyloidosis is a disease where there is deposition of amyloids in many organs. Amyloids are formed by accumulation of misfolded proteins. These misfolded proteins have a crossed β-sheet structure. These β-sheets have a property called birefringence, meaning that they can easily be seen in a polarizing microscope. A special staining called Congo red stain can be used to increase the birefringence of the amyloids, which become green under a polarizing microscope.

Amyloidosis can affect theoretically any organ, but the following organs are most commonly affected:

  • Heart
    • Causing cardiomyopathy
  • Gastrointestinal tract
    • Leading to malnutrition, diarrhoea
  • Liver and spleen
    • Causes enlargement and rubber-like consistence
  • Kidney
    • Renal failure
  • Tongue
    • Easy to biopsy to confirm amyloidosis

See theoretical topic 16 for more details on amyloidosis.

It’s important to note that the amyloids themselves aren’t toxic. They’re dangerous for tissues because they occupy the interstitial space which causes compression of the nearby cells and capillaries, damaging them.

I know Lee notes and some teacher say that it’s a spleen and not a pancreas, but I asked my group teacher and he confirmed that it’s the pancreas. Also, in my opinion, from behind the organ doesn’t look like a spleen.

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8 thoughts on “12. Systemic amyloidosis”

  1. Hello,

    I think the prep. to the right is the spleen, and not pancreas.
    However, I think it’s smart to emphasise that in kidney, amyloid deposits in glomeruli, spleen in follicles(sago spleen) or in sinuses (lardaceous spleen) and finally in liver in space of Disse and sinusoid.

  2. Hey! 🙂
    Just one note: you wrote that the cells enlarge but amyloidosis is always extracellular!
    Thanks for the preps!

  3. Hey !!!

    I got this prep during my exam and my examiner told me that it was the spleen and not the pancreas. He even asked me who was my teacher because he couldn’t believe that I said pancreas instead of spleen.
    So yea I don’t know 🤷🏼‍♀️. I don’t think it’s a big mistake because I still passed.

    1. Hey!

      Congrats on passing!

      Regarding the pancreaspleen I suppose we’ll never know what the true answer is. But, like you said, I don’t think it matters too much. Probably the best thing to do on the exam is to say that it may be either one, and just say that some teachers disagree. Whatever organ is in the prep doesn’t really matter anyway, they all have the same characteristics.

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