Page 242 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 9-2 Integumentary System
AMYLOIDOSIS Sites and manifestations of amyloid deposition that may occur in various combinations
Eyes
Skin
The term amyloidosis refers to a heterogeneous group of Alopecia—nonscarring Conjunctival plaques
Vitreous opacities
diseases. Systemic and cutaneous forms of amyloidosis Papular and nodular infiltrations Muscle weakness
can occur and are caused by the deposition of one of Purpura and petechiae Pupillary disorders
many different amyloid proteins. The primary cutane- Urticaria Proptosis
ous forms are more frequently seen. They include Amaurosis
nodular, lichen, and macular amyloidosis (also referred Esophagus
to as lichen or macular amyloidosis). The systemic Hematemesis
form is a multisystem, life-threatening disorder that Dysphagia
requires systemic therapy. Most systemic disease is Varices Tongue
caused by an abnormality in plasma cells; myeloma- Macroglossia
associated amyloid is a distant second in incidence. In Speech difficulty
addition to amyloidosis of the skin, the central nervous Liver Dysphagia
system may be involved with amyloidosis, as it is in Hepatomegaly Larynx, trachea, bronchi
Alzheimer’s disease. Hoarseness
Clinical Findings: Systemic amyloidosis is caused by Cough
abnormal production of amyloid AL protein (immuno- Pancreas Stridor
globulin light chains) and its deposition in various Diabetes mellitus Dyspnea
organ systems. These effects can be seen in patients Hemoptysis
with plasma cell dyscrasia or myeloma. Mucocutaneous Lungs
findings are often part of systemic amyloidosis, and on Stomach, intestines Asymptomatic nodules
occasion they are the initial presentation of the disease. Hematemesis
The hallmark cutaneous finding is translucent papules Bloody stools
(occult or overt)
and plaques with varying degrees of hemorrhage. These Ulceration
papules are composed of the abnormal AL protein. Diarrhea
Soft, rubbery papules may also occur within the oral Malabsorption
mucous membranes. Pinch purpura of the skin is almost Heart
universal and results from weakening of the superficial Enlargement
cutaneous vessels by deposition of the AL protein. Peri- Autonomic nerves Conduction defects
orbital ecchymoses may circumferentially surround the Incontinence Coronary insufficiency
eye, which has led to the term “raccoon eyes.” The Impotence Failure
ecchymoses may be induced by coughing or by super-
ficial trauma. The palms and soles may have a waxy Peripheral nerves Spleen
appearance. The tongue is often strikingly enlarged due Carpal tunnel Splenomegaly
to amyloid deposits. syndrome Kidneys
Deposition of the AL protein in close approximation Areflexia Proteinuria
to the dermal elastic fibers produces a rare finding Sensory loss Cylindruria
termed amyloid elastosis. Clinically, this may mimic Paresthesia Microhematuria
cutis laxa; the skin is easily distensible and lacks elastic Motor weakness Nephrotic syndrome
recoil. (in Portuguese familial type) Azotemia
Deposition of amyloid in the renal glomeruli, liver, Joints
or heart muscle can cause significant end-organ damage. Bladder, urethra Arthritis
Renal insufficiency leading to renal failure is a major Hematuria
cause of morbidity and mortality. Hepatomegaly,
leading to fibrosis and liver failure, may occur. Amyloid
protein that is deposited in the muscle of the heart may
lead to arrhythmias and congestive heart failure.
The primary cutaneous diseases known as lichen
amyloidosis and macular amyloidosis are localized to
the leg and the back, respectively. Most cases are
believed to be directly caused by keratinocyte-derived
amyloid protein. There are no systemic symptoms.
Patients present with pruritic hyperpigmented macules
and papules that may coalesce into plaques. Nodular
primary cutaneous amyloidosis is caused by the local
production of AL protein by plasma cells in the skin.
This condition is extremely rare and may progress to Extensive amyloid deposits in glomerulus of Same section, viewed under polarizing micro-
scope, demonstrating green birefringence
human kidney (Congo red and hematoxylin stain)
systemic amyloidosis.
Pathogenesis: Systemic AL amyloidosis results from
plasma cell dyscrasia or from myeloma-associated
disease. It is directly caused by a proliferation of abnor- Histology: Amyloidosis is a disease caused by the and melphalan were the agents of choice. Newer pro-
mal plasma cells. The plasma cells produce excessive abnormal deposition of amorphous AL protein in the teosome inhibitors are currently used. Bone marrow
amounts of immunoglobulin light chains, predomi- dermis and subcutaneous tissue. Biopsies of involved transplantation is performed in certain cases.
nantly λ chains. The excessive amounts of AL protein skin show eosinophilic deposits on routine staining. Therapy for primary cutaneous amyloidosis is
are deposited within the walls of the cutaneous vascu- The amyloid protein is accentuated with special stain- directed at symptomatic control. Topical corticoste-
lature; this leads to weakening of the walls and is ing methods such as the Congo red stain. It shows an roids and oral antihistamines are used to control itching.
responsible for their easy rupture. The AL protein is apple-green birefringence under polarized light micros- Varying results have been reported with ultraviolet
deposited in many organ systems. Rarely, the plasma copy and appears reddish under routine microscopy. phototherapy. No randomized, prospective studies of
cells produce immunoglobulin heavy chains; this is Treatment: Systemic amyloidosis is best treated with the treatment of primary cutaneous amyloid have been
termed AH protein. combination chemotherapy. Traditionally, prednisone published.

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