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Skin-nontumor

Other dermatoses

Pseudoxanthoma elasticum


Reviewer: Mowafak Hamodat MB.CH.B, MSc., FRCPC (see Reviewers page)
Revised: 5 November 2014, last major update August 2011
Copyright: (c) 2002-2014, PathologyOutlines.com, Inc.

Definition
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● Genetic disorder with ocular, vascular and skin lesions due to mutations of ABCC/MRP6 gene at 16p13.1, coding for ATP-binding protein, and causing degeneration of elastic fibers
● Variable penetrance, even within the same family
● Autosomal dominant or recessive, usually women
Skin: yellow streaks and plaques, particularly in creases of axillae, groin and neck; appear before puberty
Eyes: angioid streaks in retina, causing hemorrhage and visual loss
Vessels: degenerative changes in arteries causing mineralization, occlusion or rupture

Case reports
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● 26 year old with sudden death while dancing, due to intramyocardial arteriolar involvement (Hum Pathol 2000;31:1002)
● 32 year old man with multiply, yellowish, waxy papules on neck (Case of the Week #332)
● 51 year old man with plaques on arm (Dermatol Online J 2001;7:16)

Micro description
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● Affected elastic fibers are basophilic and irregular, appearing as widely dispersed granular material amidst normal collagen fibers; may have a bizarre appearance reminiscent of a bishop’s crook
● Abnormal fibers are bright pink with an altered architecture, as they have lost their normal interlacing pattern, but may be faintly basophilic due to calcium
● Increased dermal mucin may be evident
● Vascular involvement consists of fragmentation of the internal and external elastic laminae, accompanied by intimal thickening, resulting in weakness of the vessel wall and a tendency towards rupture and aneurysm formation
● Eye: calcifications of Bruch’s membrane, which separates the choroid from the pigment epithelium of the retina

Micro images
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Case of the Week #332


Case of the Week #332: Verhoeff's Van Gieson stain for elastic fibers

Positive stains
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● Verhoeff's Van Gieson stain for elastic fibers shows marked degeneration of fibers with a short and curled appearance
● Von Kossa stain reveals calcium deposition
● Fibers also stain positive with Alizarin red calcium stain

Electron microscopy
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● Fragmented and polymorphic elastic fibers in reticular dermis
● Fibers may contain finely disbursed, mineral crystals
● Similar changes in carriers

Differential diagnosis
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Cutis laxa: loss of elastic tissue in the papillary and reticular dermis; fibers are shortened, tapered and degenerate (Arch Dermatol 1965;92:373)
Late-onset focal dermal elastosis: normal elastic fibers in the mid- and deep dermis, with no evidence of calcification (Am J Dermatopathol 1999;21:381)
Penicillamine therapy: similar skin lesions, but also produces elastosis perforans, serpingiosa and collagen defects
Pseudoxanthoma elasticum-like papillary dermal elastolysis: occurs in elderly females, systemic lesions are absent; partial or complete elastolysis in the papillary dermis, but calcification is typically absent with normal collagen fibers (Br J Dermatol 1998;139:141)
● Manifestations of pseudoxanthoma elasticum, including cutaneous lesions, angioid streaks and vascular calcification, have been identified in many hemolytic conditions including beta-thalassemia, sickle cell disease and hereditary spherocytosis (Br J Haematol 2003;122:852).
Saltpeter: similar dermal changes histologically and ultrastructurally

Additional references
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eMedicine

End of Skin-nontumor > Other dermatoses > Pseudoxanthoma elasticum


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