Dermatopathology III Flashcards
Age range for pemphigus vulgaris:
30-50
Pemphigus vulgaris:
IgG autoantibodies against desmogleins 1 and 3 in desmosomes in the suprabasal deep epidermis and mucosal epithelium.
Pemphigus vulgaris blisters (2):
- Suprabasal split; acantholytic blisters
- Positive Nikolsky sign
Pemphigus foliaceus:
Autoantibodies against Dsg1; superficial, subcorneal blisters
Pemphigus vulgaris direct immunofluorescence pattern:
Net-like pattern of intracellular IgG deposits
Bullous pemphigoid age range:
Elderly
Bullous pemphigoid presents on (5):
- Inner aspects of thighs
- Flexor surfaces of forearms
- Axillae
- Groin
- Lower abdomen
Bullous pemphigoid target antigens:
BPAg1 and BPAg2 in the hemidesmosome.
Bullous pemphigoid blisters:
Subepidermal, noncantholytic blisters
Bullous pemphigoid direct immunofluorescence:
Linear deposition of C3 and IgG along dermoepidermal junction
Dermatitis Herpetiformis age range:
20-60
Dermatitis Herpetiformis etiology:
IgA autoantibodies to transglutaminases bind to TG in gut and cross-react with reticulin in fibrils in skin.
Dermatitis Herpetiformis associated with HLAs (3):
- HLA-B8
- HLA-DR
- HLA-DQ
Dermatitis Herpetiformis lesions (4):
- Symmetrically grouped
- Papules and plaques progressing to vesicles and bullae
- Buttocks, elbows, knees, scapular areas
- Very pruritic
Dermatitis Herpetiformis type of blister:
Subepidermal blister
Direct immunofluorescence of Dermatitis Herpetiformis :
Discontinuous granular deposition of IgA in tips of dermal papillae
Dermatitis Herpetiformis diagnosis (3):
- Skin biopsy
- Antiendomysial antibodies (specific for TG)
- Endoscopy: blunting of villi in small bowel
Dermatitis Herpetiformis treatment (2):
- Gluten-fee diet (slow)
- Dapsone (fast)
- Check G6PD level
Porphyria cutanea tarda age range:
30-50
Porphyria cutanea tarda etiology:
Uroporphyrinogen decarboxylase (UROD) deficiency leads to excessive accumulation of porphyrins
Porphyria cutanea tarda cause (3):
- Porphyrins make skin photosensitive
- Tense subepidermal bulla on normal appearing skin in sun exposed areas
- May also get hypertrichosis on face
Porphyria cutanea tarda diagnosis:
Test for increased uroporphyrin in urine
- Will fluoresce orange under woods lamp
Acne vulgaris pathogenesis:
Obstruction of sebaceous follicles by sebum promotes proliferation of p. acnes.
Acne rosacea age range:
30-50
Acne rosacea:
Chronic inflammatory disorder that affects blood vessels and pilosebaceous units
Acne rosacea 4 stages:
- Flushing episodes
- Persistent erythema and telangiectasias
- Pustules and papules
- Rhinophyma
Panniculitis:
Inflammation of fat lobules or the connective tissue septa separating fat lobules
Erythema nodosum age range:
20-30
Erythema nodosum:
Inflammatory reaction of connective tissue septa separating fat lobules
Erythema nodosum presents as (4):
- Painful, red, subcutaneous, elevated nodules
- Nodules indurated and poorly circumscribed
- Usually located on the anterior aspect of the tibia
- Bilateral but not symmetric
Erythema nodosum histology (3):
- Septal panniculitis (little to know necrosis of lobule)
- Early: widening of septa from fibrin, edema and neutrophilic infiltrate
- Chronic: Mononuclear cells and granulomatous inflammation of septum with fibrosis
Warts:
Benign growths caused by infection of epidermal cells with HPV
Plantar wart (3):
- HPV 1
- Flesh colored papule with hyperkeratotic surface
- Found on underside of foot
Condyloma acuminatum (3):
- Soft fleshy pink papillomas on the genitalia, perineum and anus
- HPV
- Most common STD
Molluscum contagiosum is caused by:
Poxvirus
Molluscum contagiosum lesions (3):
- Asymptomatic smooth, dome-shaped papules with central umbilication
- Flesh-colored and translucent
- Papules have a cheesy core that can be expressed
Scabies is caused by:
Infection with Sarcoptes scabiei
Xanthelasma:
Collection of macrophages containing lipid droplets
Mongolian spot:
Melanocytes located in the dermis instead of epidermis that may be neural crest cells interrupted in migration
Cherry angioma (2):
- Bright red, domed, vascular lesions on trunk
- Benign and increase with age
Hemangioma of infancy (3):
- Benign tumor of hyperplastic blood vessels
- Blanchable bright red to deep purple lesions
- Regression complete by age 10
Xeroderma pigmentosum (2):
- Autosomal recessive
- Decreased ability to repair DNA following damage by UV light due to defects in excision of abnormal nucleotides or defects in replacement of nucleotides following excision
Chediak-Higashi syndrome (2):
- Autosomal recessive
- Immunodeficiency due to defect in neutrophil phagosome lysosome fusion causing abnormal giant lysosomal inclusions visible on peripheral blood smear
Albinism:
Melanocytes normal in number and location but production of melanin defective due to complete absence of tyrosinase
