๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Hemodialysis-associated amyloidosis
Hemodialysis-associated amyloidosis
Clinical features This variant of amyloidosis, induced by beta-2-microglobulin, occurs in patients on long-term hemodialysis.1โ5 Exceptionally, cases may present after short-term hemodialysis.6 The most commonly involved organs are the heart, gastrointestinal tract, and lungs.1 Interestingly, the disease does not seem to involve the spleen.1 Carpal tunnel syndrome, polyarthralgia, and destructive spondyloarthropathy have also been documented.4,7โ9 The walls of blood vessels are often involved, whereas bone lesions are relatively rare, although pathological fractures may occur.7,9,10 Cutaneous involvement, which is very uncommon, has been reported to present as subcutaneous masses in the buttocks and shoulder, lichenoid papules and a wrinkled appearance of the skin of the palmar aspect of the fingers. 6,7,10โ13 Rare cases of amyloidoma of the tongue and external auditory canal have been reported.14โ16
Histologic features In cases with skin involvement, the amyloid deposits have been found either in the subcutaneous tissue or in the papillary and reticular dermis, around sweat glands and hair follicles.6,7,10โ13 Occasionally, special stains are unhelpful in demonstrating amyloid and confirmation of the diagnosis by electron microscopy or, mass spectroscopy can confirm the diagnosis.17
The urticarial lesions are characterized by an upper to mid-dermal infiltrate of neutrophils with a few eosinophils and dermal edema.8,9 Neutrophils are seen intravascularly and in vessel walls as well as around eccrine glands.8,9 Although vasculitis has not been described, some vessels may contain fibrinoid deposits. Histologic features of the sclerotic lesions include dermal thickening with sclerosis of collagen bundles, fragmentation and thickening of elastic fibers, focal calcification of degenerated elastic fibers, superficial and deep perivascular and interstitial infiltrate of lymphocytes and histiocytes, numerous plasma cells and admixed eosinophils and mast cells.7
Familial amyloidotic polyneuropathy Clinical features Familial amyloidotic polyneuropathy is an autosomal dominant disease in which the deposition of amyloid occurs predominantly in peripheral nerves. The amyloid deposits in this disease consist in most cases of variant transthyretin with single amino acid substitutions.1โ3 Clinical manifestations include sensory then motor peripheral neuropathy predominantly affecting the limbs and autonomic dysfunction manifesting as alternating diarrhea and constipation, urinary incontinence, orthostatic hypotension, and sexual dysfunction.3 The cutaneous manifestations comprise nonhealing ulcers, multiple atrophic scars, and anhidrosis of the lower limbs.4,5 Patients may also have seborrheic dermatitis, acne, and onychomycosis, though some of these may be coincidental.6 In some patients petechiae can be induced by gentle stroking of the skin.
577 The amyloidoses
Histologic features Histologically, biopsies from clinically normal skin reveal the presence of amyloid in blood vessel walls, sweat glands, and arrector pili muscle.4