47- Amyloidosis

Question 1

What are the three major forms of primary cutaneous amyloidosis

Answer 1

1. macular amyloidosis
2. lichen amyloidosis
3. nodular amyloidosis
4. biphasic amylodosis.

Question 2

What races is primary cutaneous amlyosis usually seen in?

Answer 2

• 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.

Question 3

How can amyloidosis be classified?

Answer 3

• systemic (primary and secondary_

- localised

Question 4

What are some possible etiologic factors for primary cutaneous amyloidosis?

Answer 4

• EBV
• Environmental factors
• prolonged friction
• genetic predisposition

Question 5

What antibodies stain positive in cutaneous amyloidosis/

Answer 5

• antibodies against IgG, IgM and IgA

Question 6

in nodular amyloidosis what stains are positive?

Answer 6

no specific stains are positive with antikeratin antibodies.

Question 7

in nodular amyloidosis what are the amyloid deposits composed of?

Answer 7

immunogloublin light chains. (suggeting plasma cell derivation).

Question 8

What is seen histologically in amyloidosis?

Answer 8

• 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.

Question 9

What stains can be used to detect amyloidosis?

Answer 9

• congo red

- other stains include crystal voilet, PAS, Dylon, sirius red, pagoda red, dylon stain, thioflavin T.

Question 10

What amyloid precursor protein is found in primary systemic amyloidosis?

Answer 10

• light chains (seen more than heavy chain)

Question 11

What is seen on electron microscopy?

Answer 11

• 7-10 mm non-branching, non anastomosing fibrils

- cross B pleated sheet and conformation.

Question 12

What are the clinical manifestations of macular amyloidosis?

Answer 12

• 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.

Question 13

what are the clinical manifestations of lichen amyloidosis?

Answer 13

• persistent pruritic plaques on the shins or other extensor surfaces of the extremities.
• lesions are discrete, firm scaly skin coloured or hyperpigmenbted papules.

Question 14

What conditions are associated with primary cutaneous amyloidosis?

Answer 14

pachyonychia congentia, dyskeratosis congenita and familial palmoplanta keratoderma.

Question 15

What is dyschromic amyloidosis?

Answer 15

guttate leukoderma is superimposed on a background of hyperpigmentation and a mix of lesions of macular and lichenoid amyloidosis

Question 16

what conditions are macular and lichenoid amyloidosis associated with?

Answer 16

autoimmune connective tissue disorders including scleroderma, systemic lupus erythematousus, dermatomyositis and primary biliary cirrhosis.

Question 17

what is the clinical presentation of nodular amyloidosis?

Answer 17

• presents as single or multiple waxy nodules or infiltrated plaques on the the trunk or extremities.

Question 18

what are the differential diagnosis of macular amyloidosis?

Answer 18

• PIH
• atrophic lichen planus
• erythema dyschromicum perstans
• phototoxic contact dermatitis
• drug induced pigmentation

Question 19

what are the differentials for lichen amyloidosus?

Answer 19

• lichen simplex chronicus

- hypertrophic lichen plaus.

Question 20

what is the treatment ladder for macular and lichenoid amyloidosis?

Answer 20

• potent topical corticosteroids under occlusion
• topical calcineurin inhibitors
• intralesional corticosteroids
• UVB photothreapy
• PUVA photothreapy
• systemic retinoids
• dermabrasion
• laser
• CO2 laser
• low dose cyclophosphamide
• cyclosporin.

Question 21

what is primary systemic amyloidosis associated with?

Answer 21

• underlying plasma cell dyscraisias.
• fibrils composed of AL light chain proteins- usually gama chains

myeloma associated amyloidosis is also AL amyloidosis

Question 22

what are the clinical features of primary systemic amyloidosis?

Answer 22

- 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

Question 23

where is the best place for biopsies in amyloidosis?

Answer 23

• rectal mucosa biopsies or abdominal subcutaneous fat aspirates.

Question 24

what is the treatment of systemic amyloidosis?

Answer 24

• high-dose melphalan = autologous peripheral blood stem cell transplantation.