Amyloidosis Flashcards
What is amyloid?
Amyloid is fibril proteins that arrange in beta-sheets.
AA and AL are two common categories
What is the histology of amyloid and what is the stain used to see it?
Appears as homogenous, pink, fissued areas (cotton candy) that stain with Congo Red stain and turn apple green (birefringence) w/ polarized light
What stains stain amyloid?
Congo red (classic), crystal violet, PAS, and thioflavin T
What causes AA amyloid to lose its affinity for Congo Red stain?
Exposure to potassium permanganate
What are the 5 types of cutaneous amyloid?
Primary, secondary, genetic, hemodialysis-associated (Beta2 microglobulin), localized
What are the 3 types of localized amyloidosis?
Macular, lichenoid, nodular
What are the clinical characteristics of macular amyloidosis and where does it most commonly present?
Presents as a “salt and pepper” confluent or rippled pruritic, hyperpigmented patch.
- Most common location is the interscapular back
What is the protein and the derivation of macular amyloid?
Protein: Aker
Derivation: Keratinocyte tonofilaments (usually keratin 5)
What is the histology of macular amyloid?
Amyloid is noted in the papillary dermis
What is the clinical appearance and most common location of lichen amyloid?
Rippled, hyperpigmented, pruritic papules/plaques on extensor surfaces. (most commonly the shins)
What disorder can macular amyloid be commonly seen in?
Notalgia paraesthetica
What is the protein and derivative for lichen amyloid?
Derivative: keratinocyte tonofilaments most commonly keratin 5
Protein: Aker
What is the clinical appearance of nodular amyloid and what are the most common sites?
Pink to yellow waxy nodules (smooth) and/or plaques. These are most commonly seen on the face or acral surfaces
What is the derivation and the protein for nodular amyloid?
Derivative: Ig light chains
Protein: AL
Note that this is the only localized primary amyloidosis that is not from keratin!
In what groups is localized amyloidosis more commonly seen?
Asians, Hispanics, and Middle Easterners
Treatment options for localized amyloidosis?
No great tx options. Can try topical corticosteroids, phototherapy/laser to surgery
What is the protein and derivation of primary systemic amyloidosis?
Derivation: Ig light chains (usually kappa subtype)
Protein: AL
What is the organ system carries the worst prognosis in primary systemic amyloidosis?
It can involve any number of organ systems, but cardiac carries the worst prognosis
What percentage of patients with primary systemic amyloidosis have mucocutaneous findings?
One third
What causes systemic primary amyloidosis?
Underlying plasma cell dyscrasia (15% with myeloma)
What can be the clinical mucocutaneous findings in primary systemic amyloidosis?
Papules/nodules/plaques that are translucent, or purpuric. Ecchymosis/pinch purpura (eyelids, neck, anogenital, or axillary)[BIG FOR BOARDS]. Can see bullous amyloid
- Macroglossia (you can see teeth indentation on side of tongue
- carpal tunnel syndrome
- Can have sclerodermoid presentation w/ alopecia and cutis verticis gyrata-like scalp changes (these look like the folds of a shar-pei dog)
What is the histology of systemic primary amyloidosis (cutaneous)
Amyloid throughout the dermis and subcutis, in sweat glands, and blood vessel walls
What labs should be checked if there is evidence of primary systemic amyloidosis (cutaneous)
UPEP/SPEP, and immunofixation (IFE) (besides basic labs)
What are some causes of secondary amyloidosis?
Ankylosing spondylitis, Tb, HA, dystrophic EB, scleroderma, and autoinflammatory syndromes like Muckle-Wells
What is the protein in secondary systemic amyloidosis and how does it end up in the skin (or other organs)?
The protein is Serum amyloid A (SAA) which gets converted to AA amyloid in the tissues
What organ systems are most commonly involved in secondary systemic amyloidosis?
Skin is rarely affected, usually involves kidneys, liver, spleen, adrenals, and heart
Amyloidosis in hemodialysis patients is made up often of beta 2 microglobulin (Abeta2microglobulin) usually no skin involvement but can have subcutaneous nodules on the lower back
