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Category Archives: Skin
Neurocutaneous Syndromes
Neurocutaneous Syndromes
Neurocutaneous Syndromes types:
1. Neurofibromatosis I and II
2. Tuberous sclerosis
3. von Hippau Lindau syndrome
4. Sturge-Weber
Posted in Skin
Tagged Neurocutaneous, Neurocutaneous Syndrome, Neurocutaneous Syndromes, Neurofibromatosis, Neurofibromatosis I, Neurofibromatosis II, Sturge Weber, Tuberous sclerosis, von Hippau Lindau syndrome
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Glomus Tumor
Glomus Tumor
Clinical presentation:
- seen in distal extremities and stomach
- subungual (painful here)
- mainly women
Gross appearance:
- small with mucosal ulceration
Histology:
- small round epithelioid cells that surround dilated blood vessels
Immunohistochemistry:
- actin, h-caldesmon, collagen type 4
Electron microscopy:
- cytoplasm packed with myofilaments with focal condensations
Posted in Skin
Tagged , Collagen type 4, Glomus, Glomus tumor, Glomus tumor skin, Glomus tumor stomach, h-caldesmon
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Scleroderma
Scleroderma
Definition:
Chronic autoimmune disease with:
1. excessive deposition of collagen throughout the body
2. vascular intimal fibrosis resulting in microvascular disease
Etiology:
Autoimmune disease leading to an activation of T cells with release of cytokines, and recruitment of mast cells and macrophages
Syndrome:
CREST syndrome (calcinosis, raynaud’s, esophageal dysfunction, scelerodactyly, telangectiasia)
Lab tests:
ANA :
- DNA topoisomerase I (very specific)
- anti-centromere antibody
Pathology:
Skin:
- thining of the epidermis
- dermal appendage atrophy
- fibrosis of the dermis
→ claw-like flexion deformity
GI:
Esophagus: replacement of the muscularis by collagen resulting in garden hose tube → reflux, Barrett’s esophagus, dysphagia
Intestine: loss of villi and microvilli → malabsorption
Joints: hypertrophy with fibrosis of synovium.
Kidneys:
- intimal thickening and concentric proliferation of intimal cells
Malignant Hypertension: fibrinoid necrosis with thrombosis and infarction → acute renal failure
Lungs: pulmonary fibrosis and vascular changes → can result in → pulmonary hypertension and right heart failure
Heart: myocardial fibrosis and thickening of intra-myocardial arterioles → CHF, arrythmias
Posted in Skin
Tagged , anti-centromere antibody, calcinosis, CREST, CREST syndrome, DNA topoisomerase I, raynauds. esophageal dysfunction, scelerodactyly, Scleroderma, telangectiasia
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Scleroderma
Scleroderma
What is Scleroderma ?
Scleroderma is a chronic autoimmune disease with:
1. excessive deposition of collagen throughout the body
2. intimal fibrosis resulting in microvascular disease
Causes:
- activation of T cells with release of cytokines, and recruitment of mast cells and macrophages
CREST syndrome
Associated syndrome: CREST syndrome (calcinosis, raynaud’s, raynaud’s phenomenon, esophageal dysfunction, scelerodactyly, telangectasia)
Lab tests:
ANA :
-DNA topoisomerase I (very specific)
-anti-centromere Ab
Pathology:
Skin:
-thining of the epidermis
-dermal appendage atrophy
-fibrosis of the dermis → clawlike flexion deformity
GI:
Esophagus: replacement of the muscularis by collagen resulting in garden hose tube → reflux, Barrett’s, dysphagia
Intestine: loss of villi and microvilli → malabsorption
Joints: HP and hypertrophy with fibrosis of synovium.
Kidneys:
-intimal thickening and concentric proliferation of intimal cells
Malignant HP: fibrinoid necrosis with thrombosis and infarction
Lungs: pulmonary fibrosis and vasc. changes→can result in → pulm HTN and RHF
Heart: myocardial fibrosis and thickening of intra-myocardial arterioles → CHF, arrythmias
Posted in Skin
Tagged autoimmune disease, calcinosis, CREST syndrome, esophageal dysfunction, Intimal fibrosis, raynaud’s, raynaud’s phenomenon, scelerodactyly, Scleroderma, Scleroderma histology, Scleroderma lab tests, Scleroderma pathology, telangectasia
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Systemic Lupus Erythematosus
Systemic Lupus Erythematosus
What is Systemic Lupus Erythematosus ?
Systemic Lupus Erythematosus is a chronic autoimmune disease with a variable course which affects the skin, joints, kidney and serosal membranes. Seen mainly in women.
Clinical features: MD BRING SOAP!
Malar rash
Discoid rash
Blood (anemia, thrombocytopenia, leukopenia)
Renal: proteinuria, casts
Immunologic:
ANA (anti dsDNA, anti-Sm (Smith)), anti-phospholipid
Neurologic (seizures and psychosis)
Genetic predisposition (increase risk with family members)
Serositis
Oral ulcers
Arthritis
Photosensitivity
Different types of indirect immunofluorescence staining patterns:
1. Homogeneous
2. Rim
3. Speckled
4. Nucleoli
Systemic Lupus Erythematosus Kidney:
Class I:Normal LM, IF, EM
Class II: Mesangial lupus (mild ↑ in mesangium + granular mesangial deposits)
Class III: Focal proliferative GN (focal necrotizing lesions in the glomerulus) <50% glomeruli
-1-2 tufts with endothelial, mesangial proliferation
-+/- fibrinoid necrosis +/-fibrin thrombi
Class IV: Diffuse proliferative GN (hypercellular+/- fibrinoid necrosis)→ this is bad. gross hematuria and nerphrotic syndrome. “wire loop lesions”. most glomeruli.
-entire glomerulus endothelial, mesangial proliferation
-+/- fibrinoid necrosis +/-fibrin thrombi
-crescent proliferation
Class V: Membranous GN (widespread thicknening of capillary walls “wire loop”)
-membranous”→ thickening of blood vessel walls
Immunofluorescence staining: Full house “IgG, M, A” and Complement: granular staining of the mesangium and basement membrane
Skin: vacoular interface dermatitis, vasculitis and fibrinoid necrosis, granular Ig and C deposit at basement membrane
Joints: non-erosive synovitis
Heart
Pericarditis: acute/subacute/chronic fibrinous exudate. Myocarditis. rare. Valve: Libman Sacks non-bacterial verrucous endocarditis
Splenomegaly with plasma cells
Lungs: pleuritis and pleural effusions
Clark’s Nevi
Clark’s Nevi
Dysplastic nevi of skin
Clinical features
· Larger than most acquired nevi (>5 mm across)
· May occur as hundreds of lesions on the body
· Flat macules, slightly raised plaques with a pebbly surface, or target-like lesions with a dark raised centre and an irregular flat periphery
· Show variability in colour (variegation) and borders that are irregular in contour
· Can occur on sun-exposed as well as non-sun-exposed areas
Histology
· Atypical proliferating melanocytes (irregular, angulated nuclear contours with hyperchromasia) at dermal-epidermal junction, without pagetoid spread (lentiginous hyperplasia)
· Elongation of rete ridges, sometimes forming bridges
· Lamellar fibrosis in papillary dermis around melanocyte nests and rete ridges
· Extension of epidermal component beyond edges of dermal component (“shoulder effect”)
· Sparse lymphocytic infiltrate with melanin pigment incontinence
Differential diagnosis from malignant melanoma
· No evidence of pagetoid spread
· Lamellar fibrosis not present in malignant melanoma
· Maturation of nevus cells in dysplastic compound nevus (smaller, more mature nevus cells at deepest portions of lesion)
Dysplastic nevi clinical significance
· Dysplastic nevi are considered to be precursors to malignant melanoma
· Patients with dysplastic nevus syndrome are predicted to have a 56% chance of developing malignant melanoma at age 59 years
Posted in Skin
Tagged , Atypical nevi, Clark's nevus, clarks nevi, dysplastic nevi, dysplastic nevus, Nevi with architectural disorder
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Keratoacanthoma
Keratoacanthoma
Clinical features
· Rapidly developing neoplasm that may be difficult to distinguish from squamous cell carcinoma clinically
· Often heals spontaneously without treatment
· Males affected more than women
· Found on sun-exposed skin of white people aged 50 or older
· Appear as flesh-coloured, dome-shaped nodules with a central, keratin-filled plug imparting a crater-like topography
· Lesions are found on facial skin (cheeks, nose, ears) as well as dorsa of hands
Gross and microscopic appearances
· Gross
o Lesions are one to several centimeters in diameter
o Dome-shaped nodules with crater-like appearance due to central, keratin-filled plug
· Microscopic
o Characterized histologically by central, keratin-filled crater surrounded by proliferating epithelial cells that extend upward in a lip-like fashion over the sides of the crater and downward into the dermis as irregular tongues
o Cells have a “glassy”, eosinophilic cytoplasm and produce keratin abruptly without an intervening granular layer
o The early tumour infiltrates into the collagen and elastic fibres and entraps them; little host inflammatory response is seen during this rapidly proliferative phase
o A fibrotic stromal response with numerous inflammatory cells develops as the lesion evolves
Differential diagnosis from squamous cell carcinoma
· Keratoacanthoma has characteristic dome-shaped, crater-like appearance with central, keratin-filled plug
· Squamous cell carcinoma often appears as sharply-defined, red, scaly plaques or nodular lesions with hyperkeratosis and ulceration
· Keratoacanthomas grow rapidly and undergo spontaneous regression with no treatment
· SCC develops over time and does not undergo regression but spreads locally and to lymph nodes
· Well-differentiated SCC may be very difficult to distinguish from KA clinically
· KA is thought to be a form of SCC that regresses as a consequence of interactions with host tissues that fail to support its growth
· Like most SCC, KA possesses mutations in the p53 gene
Type I Hypersensitivity Reactions
Type I Hypersensitivity Reactions
o Immune system release vasoactive and spasmogenic substances that act on smooth muscle and vessels and release pro-inflammatory cytokines that recruit inflammatory cells
o Antigen binds to IgE attached to mast cells—crosslinking of IgE antibodies occurs which leads to mast cell degranulation and release of preformed (primary) mediators (histamine, proteases, acid hydrolases, heparin, chondroitin sulphate)
o Also leads to synthesis and release of secondary mediators (leukotrienes, prostaglandins, PAF, cytokines)
o Leads to vascular dilatation, smooth muscle contraction, edema, mucus production, inflammation (eosinophil-rich exudate)
Type II Hypersensitivity Reactions
Type II Hypersensitivity Reactions
o Mediated by antibodies directed to antigens present on cell surfaces or extracellular matrix
o Immunoglobulins (IgG, IgM) bind to antigen on target cell/tissue leading to phagocytosis, lysis or antibody-mediated cellular cytotoxicity of the target cell/tissue via complement activation or Fc receptor recognition; also leads to leukocyte recruitment leading to inflammation
o Leads to cell lysis and inflammation
Type III Hypersensitivity Reactions
Type III Hypersensitivity Reactions
o Antibody-antigen complexes produce tissue damage by eliciting inflammation at the sites of deposition
o Deposition of antigen-antibody complexes causes complement activation and recruitment of leukocytes by complement products and Fc receptor recognition
o Results in the generation or release of pro-inflammatory substances such as prostaglandins, vasodilator peptides, chemotactic substances, proteases and reactive oxygen species
o Causes necrotizing vasculitis, inflammation
Posted in Skin
Tagged , Hypersensitivity Reactions, Type III Hypersensitivity Reactions
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