47- Amyloidosis Flashcards
What are the three major forms of primary cutaneous amyloidosis
- macular amyloidosis
- lichen amyloidosis
- nodular amyloidosis
- biphasic amylodosis.
What races is primary cutaneous amlyosis usually seen in?
- Singapore, Tawain, Thailand.
- Lichen Amylodosus is seen in chinese
- Macular amyloidosis is seen in Central and South American countries.
macular and lichen amyloidosus occur more frequently in patients with skin phototypes III and IV.
- macular and lichenoid variants of amyloidosis are thought to be keratinocyte derived.
How can amyloidosis be classified?
- systemic (primary and secondary_
- localised
What are some possible etiologic factors for primary cutaneous amyloidosis?
- EBV
- Environmental factors
- prolonged friction
- genetic predisposition
What antibodies stain positive in cutaneous amyloidosis/
- antibodies against IgG, IgM and IgA
in nodular amyloidosis what stains are positive?
no specific stains are positive with antikeratin antibodies.
in nodular amyloidosis what are the amyloid deposits composed of?
immunogloublin light chains. (suggeting plasma cell derivation).
What is seen histologically in amyloidosis?
- amorphous eosinophilic fissured material
- green birefringence under polarized light
- amyloid deposits restricted to the upper dermis - especially the papillary dermis.
- sparse perivascular lympohistiocytic infiltrates.
in the nodular variant the dermis, subcutis and blood vessel walls are diffusely infiltrated with amyloid.
What stains can be used to detect amyloidosis?
- congo red
- other stains include crystal voilet, PAS, Dylon, sirius red, pagoda red, dylon stain, thioflavin T.
What amyloid precursor protein is found in primary systemic amyloidosis?
- light chains (seen more than heavy chain)
What is seen on electron microscopy?
- 7-10 mm non-branching, non anastomosing fibrils
- cross B pleated sheet and conformation.
What are the clinical manifestations of macular amyloidosis?
- maybe pruritic or asymptomatic.
- hyperpigmented and confluent or rippled.
- commonly found on the upper back especially the scapular and the extensor surfaces of the extremities.
- women are affected more than men.
what are the clinical manifestations of lichen amyloidosis?
- persistent pruritic plaques on the shins or other extensor surfaces of the extremities.
- lesions are discrete, firm scaly skin coloured or hyperpigmenbted papules.
What conditions are associated with primary cutaneous amyloidosis?
pachyonychia congentia, dyskeratosis congenita and familial palmoplanta keratoderma.
What is dyschromic amyloidosis?
guttate leukoderma is superimposed on a background of hyperpigmentation and a mix of lesions of macular and lichenoid amyloidosis
what conditions are macular and lichenoid amyloidosis associated with?
autoimmune connective tissue disorders including scleroderma, systemic lupus erythematousus, dermatomyositis and primary biliary cirrhosis.
what is the clinical presentation of nodular amyloidosis?
- presents as single or multiple waxy nodules or infiltrated plaques on the the trunk or extremities.
what are the differential diagnosis of macular amyloidosis?
- PIH
- atrophic lichen planus
- erythema dyschromicum perstans
- phototoxic contact dermatitis
- drug induced pigmentation
what are the differentials for lichen amyloidosus?
- lichen simplex chronicus
- hypertrophic lichen plaus.
what is the treatment ladder for macular and lichenoid amyloidosis?
- potent topical corticosteroids under occlusion
- topical calcineurin inhibitors
- intralesional corticosteroids
- UVB photothreapy
- PUVA photothreapy
- systemic retinoids
- dermabrasion
- laser
- CO2 laser
- low dose cyclophosphamide
- cyclosporin.
what is primary systemic amyloidosis associated with?
- underlying plasma cell dyscraisias.
- fibrils composed of AL light chain proteins- usually gama chains
myeloma associated amyloidosis is also AL amyloidosis
what are the clinical features of primary systemic amyloidosis?
- fatigue weight loss paraesthesias dyspnoea syncopal attack
- tongue is enlarged and firm
- hemaorrhagic papules on the surface.
- purpura around the eyelids
- waxy nodules on the bdoy
- may have bullous lesions
- macroglossia +carpal tunnel syndrome –> think o systemic amyloidosis
- renal manifestations (proteinuria, hypoalbuminemia and edema).
- cardiac involvement
where is the best place for biopsies in amyloidosis?
- rectal mucosa biopsies or abdominal subcutaneous fat aspirates.
what is the treatment of systemic amyloidosis?
- high-dose melphalan = autologous peripheral blood stem cell transplantation.
