Table of Contents
Definition / general | Clinical features | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Additional referencesCite this page: Hamodat M. Porphyria. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorporphyria.html. Accessed September 25th, 2023.
Definition / general
- Noninflammatory blistering disorder due to disturbance of porphyrin metabolism (porphyrins are present in hemoglobin, myoglobin and cytochromes)
Clinical features
- 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
Microscopic (histologic) description
- 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
Microscopic (histologic) images
Positive stains
- 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