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Skin-nontumor

Blistering disorders

Porphyria


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

Definition
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● Non-inflammatory blistering disorder due to disturbance of porphyrin metabolism (porphyrins are present in hemoglobin, myoglobin and cytochromes)

Clinical features
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● Urticaria and vesicles that heal with scarring, and are exacerbated by sunlight
Types: acute intermittent, congenital erythropoietic, hepatoerythropoietic porphyria, porphyria cutanea tarda and mixed
Acute intermittent porphyria: second most common type of porphyria but still rare; autosomal dominant metabolic disorder with porphobilinogen deaminase deficiency; typically asymptomatic, but triggered by hormones, drugs and dietary changes; presents with abdominal pain or psychiatric symptoms; skin is typically not involved
Congenital erythropoietic porphyria: rare autosomal recessive disease with mutation in uroporphyrinogen-III synthase gene, leading to porphyrin accumulation in many tissues with marked skin photosensitivity, hemolytic anemia with splenomegaly and decreased life expectancy
Hepatoerythropoietic porphyria: rare (<50 cases reported) autosomal recessive form of porphyria cutanea tarda, with markedly deficient activity of uroporphyrinogen decarboxylase (UROD); manifests during infancy or early childhood with extreme photosensitivity, skin fragility in sun-exposed areas, hypertrichosis, erythrodontia and pink urine; may resemble child abuse (Arch Dermatol 2010;146:529)
Porphyria cutanea tarda: Most frequent type of porphyria; autosomal dominant disorder due to catalytic deficiency of uroporphyrinogen decarboxylase (UROD), the fifth enzyme in heme biosynthesis (Best Pract Res Clin Gastroenterol 2010;24:735); reduced complement deposition during clinical remission (An Bras Dermatol 2010;85:827)

Clinical images
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Porphyria cutanea tarda


Porphyria cutanea tarda


Hepatoerythropoietic porphyria

Micro description
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● Subepidermal vesicle, marked thickening of superficial dermal vessels (may appear rigid)
● No/minimal inflammation
Porphyria cutanea tarda: dermal papillae protrudes into bulla with festooned pattern; roof of blister has eosinophilic, PAS+, and diastase resistant linear globules

Micro images
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Porphyria cutanea tarda


Porphyria cutanea tarda associated with HIV. Subepidermal bulla formation has resulted in loss of the epidermis. Note the rigid papillary dermal capillary walls.

   
Porphyria cutanea tarda: intense IgG staining on dermal size of basement membrane and around dermal blood vessels

Positive stains
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● IgG; to lesser extent IgM, fibrinogen and C3, outline donut–shaped blood vessels in the papillary dermis
● Immunoreactivity also at the dermo-epidermal junction and within basement membrane region of eccrine sweat glands and ducts

Additional references
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eMedicine, National Library of Medicine

End of Skin-nontumor > Blistering disorders > Porphyria


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