Kajsa Affolter, MD

Amyloid is an amorphous, acellular, eosinophilic substance image as seen on H&E section in this case of nodular amyloidosis.

In this image, amyloidosis is demonstrated by waxy indurated papules image on the eyelids. There is also a shave biopsy site on the right upper eyelid image, which confirmed the diagnosis.



  • Generic term denoting extracellular tissue deposition of eosinophilic fibrils composed of altered autologous proteins


6 Important Amyloid Proteins in Cutaneous Pathology

  • Amyloid light chain (AL) is derived from immunoglobulin light chains

  • Amyloid A protein (AA) is an HDL3-associated lipoprotein and an acute phase reactant

  • Amyloid transthyretin protein (ATTR) is present in certain heritable amyloidosis syndromes

  • Aβ-2-microglobulin protein induced by β-2-microglobulin glycosylated polypeptide

  • Amyloid keratin protein (AK) in primary cutaneous amyloidosis derived from filamentous degeneration of keratin filaments

Systemic Amyloidosis (SA)

  • Primary systemic amyloidosis; often involves skin

    • Deposition of AL (kappa or lambda)

    • May be multiple myeloma (MM) associated

    • Occurs in approximately 1/3 of patients with MM

  • Secondary systemic amyloidosis

    • Usually no skin involvement

    • Deposition of AA, amyloid A, or derived from β-2-microglobulin following long-term hemodialysis

  • Heritable amyloidosis

    • Includes entities such as familial Mediterranean fever, Muckle-Wells syndrome, familial cold autoinflammatory syndrome, and familial amyloidotic polyneuropathy

  • Amyloid elastosis

    • Rare entity with cutaneous lesions and progressive systemic disease

Primary Localized Cutaneous Amyloidosis (PLCA)

  • Macular amyloidosis (MA)

    • Deposition of AK, amyloid keratin protein, which is a keratin intermediate filament

  • Lichen amyloidosis (LA)

    • Deposition of amyloid keratin protein (AK), which is a keratin intermediate filament

  • Nodular amyloidosis (NA)

    • Deposition of amyloid light chain (AL) has been shown in many cases

  • Poikilodermatous amyloidosis

    • Rare form of localized cutaneous amyloidosis

  • Anosacral amyloidosis

    • Rare form of localized cutaneous amyloidosis



  • Age

    • PLCA: Predominantly adult population with earliest cases appearing around puberty

  • Gender

    • MA: Affects females more than males

    • LA: Affects genders equally

  • Ethnicity

    • SA: In developed countries, AL is most frequently deposited precursor protein, whereas in developing countries AA is most frequently deposited precursor protein

    • MA is seen with increased frequency in patients from Middle East, Asia, and Central and South America

    • LA is seen with increased frequency in patients from Southeast Asia


Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Amyloidosis

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