Histopath Flashcards
(503 cards)
Layers of the skin
Epidermis
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum (langerhans cells)
- Startum basale (melanocytes)
- Keratinocytes move up as they age
Dermis
- made of collagen and elastic fibres
- contains sweat glands, sebaceous glands, hair follicles, neurovascular bundles, blood vessels
Subcutaneous fat
- yum insulation
What are the inflammatory reaction changes and examples of vesiculobullous conditions?
Forms bullae
- Bullous pemphigoid
- Pemphigus vulgaris
- Pemphigus foliaceus
What are the inflammatory reaction changes and examples of spongiotic conditions?
Becomes oedematous due to intracellular oedema
- Eczema
- Contact dermatitis
What are the inflammatory reaction changes and examples of psoriasiform conditions?
Becomes thickened
- Psoriasis
What are the inflammatory reaction changes and examples of lichenoid conditions?
Forms a sheeny plaque
- Lichen planus
What are the inflammatory reaction changes and examples of vasculitic conditions?
Associated with vasculitides
- Pyoderma gangrenosum
- Small vessel vasculitis
What are the inflammatory reaction changes for granulomatous conditions?
Associated with granulomas
What do the following words mean?
a) hyperkeratosis
b) parakeratosis
c) acanthosis
d) acantholysis
e) lentiginous
a) increase in S. corenum/ keratin
b) nuclei in S corneum
c) increase in S. spinosum
d) decreased cohesions between keratinocytes
e) linear pattern of melanocyte proliferation within epidermal basal cell layer
Compare acute and chronic histology of dermatitis/eczema
Acute
- spongiosis
- inflammatory infiltrate in dermis
- dilated dermal capillaries
Chronic
- acanthosis
- crusting, scaling
Differences between atopic, contact, and seborrhoeic dermatitis
Clinical presentation
Atopic
- infants (face + scalp) and older (flexural areas) affected
- lichenification if chronic
- FHx of atopy
Contact
- type IV hypersensitivity
- erythema, swelling, pruritus
- affect ear lobes, neck, wrists, feet (jewellery, watches, shoes)
Seborrhoeic
- inflammatory reaction to yeast
- infants (cradle cap) and adults (face, eyebrow, eyelid, chest)
- mild erythema, fine scaling, mildy pruritic
What would you see in histology of psoriasis?
Parakeratosis
Loss of granular layer
Clubbing of rete ridges giving ‘test tubes in a rack’ appearance
Munro’s microabscesses
What other conditions/signs are associated with psoriasis?
Nail changes (POSH)
- Pitting
- Onycholysis
- Subungual Hyperkeratosis
Arthritis (5-10%)
Describe lesions seen in lichen planus?
Pruritic, Purple, Polyglonal, Papules and Plaques with mother-of-pearl sheen
Wickam’s striae also seen - fine white network on surface
What would you see in histology of lichen planus?
Hyperkeratosis with saw-toothing of rete ridges and basal cell degeneration
Name causes of erythema multiforme
Infections
- HSV, mycoplasma
Drugs (SNAPP)
- Sulphonamides
- NSAIDs
- Allopurinol
- Penicillin
- Phenytoin
Pt has annular target lesions on the extensor surfaces of their hands and feet
Combination of macules, papules, urticarial weals, vesicles, bullae and petechiae noted
What is this?
Erythema multiforme
Based on where IgA Abs bind to, which bullous disease is it?
a) Basement membrane -> subepidermal bulla
b) Desmoglein 1 + 3 -> intraepidermal bulla
c) Hemidesmosomes of basement membrane -> subepidermal bulla
a) Dermatitis herpetiformis
- associated w coeliac
b) Pemphigus vulgaris
- pemphiguS - bullae are SUPERFICIAL
c) Bullous pemphigoid
- pemphigoiD - bullae are DEEP
Histology shows microabscesses w coalesce to form supepidermal bullae, and neutrphil + IgA deposits as tips of dermal papillae
What is it?
Dermatitis herpetiformis
Histology shows supepidermal bullae with eosinophils, and linear depositiong og IgG along basement membrane
What is it?
Bullous pemphigoid
Histology shows intraepidermal bulla with netlike pattern of intercellular IgG deposits, and acantholysis
What is it?
Pemphigus vulgaris
Compare clinical presentation of bullous diseases
Dermatitis herpetiformis
- itchy vesicles on extenson surfaces of elbows, buttocks
- associated w coeliac
Bullous pemphigoid
- large tense bullae on erythematous base, do not rupture easily
- forearms, groin, axillae
- occur in elderly
Pemphigus vulgaris
- easily ruptured bullae
- raw red surface found on skin and mucosal membranes
- +ve Nikolsky’s sign (top layer of skin slips away from lower layer when rubbed)
Salmon pink rash appears followed by oval macules in Christmas tree distribution. Pt had a cold last week.
What is it?
Pityriasis rosea
- first patch is known as Herald patch
- remits spontaenously
Name two derm emergencies and what you would see
Stevens Johnson Syndrome
Toxic Epidermal Necrolysis
- sheets of skin detachment (<10% in SJS and >30% in TEN)
- Nikolsky sign positive
- commonly caused by reaction to drugs, i.e. sulfonamide abx, anticonvulsants
Rough plaque, waxy, ‘stuck on’ appearing in middle age/elderly
Histo shows entrapped keratin with orderly proliferation of epidermis
Seborrhoeic keratosis
- entrapped keratin = horn cysts
- benign