Histopathology 11 - Dermatopathology Flashcards
Give an example of vesiculobullous inflammation?
Bullous pemphigoid
What are the aetiological agents of pemphigoid
IgG and C3
They attack the basement membrane and destroy the adhesion molecules
How can you confirm the diagnosis of pemphigoid?
Immunofluorescence of fresh samples to show IgG and C3
What causes pemphigus vulgaris?
Pemphigus antibody attacks proteins that holds cells together in the stratum spinosum, causing “akantholysis”, which leads to formation of *suprabasilar bulla*
On which surfaces does psoriasis tend to present?
Extensor
On which surfaces does eczema tend to present?
Flexor
What is the appearance of basal cell carcinomas?
Pearly white border
Central area of ulceration
What do pre-cancerous skin cells (Bowen’s disease) look like histologically?
Pleomorphic
Atypical mitotic figures
All within the epidermis
What is the upward spread of melanocytes known as?
Pagetoid spread
When would mitotic figues in the skin not be alarming?
Pregnancy
The Breslow thickness is used to stage which skin cancer?
Malignant melanoma
Which common skin cancer does not metastasise?
Basal cell carcinoma
Is diameter or thickness more important for malignant melanoma?
Thickness
Which patient group is most at risk of pemphigus foliaceus?
The elderly - but it’s rare
Which cells of the immune system are most involved in eczema?
T-cell mediated pathology
Eosinophils recruited to sites of inflammation
Where does fluid build in eczema?
Between keratinocytes
Which skin pathology appears as “silvery plaques”?
Psoriasis
Which immune-mediated skin condition causes a rapid turnover of keratinocytes?
Psoriasis
Which skin condition appears as white lines?
Lichen planus
Which skin condition appears as a “pigmented cauliflower”?
Seborrhoeic keratosis
Which skin condition forms “keratin horns”?
Seborrhoeic keratosis
Describe the appearance of a sebaceous cyst?
Round, smooth surface, central punctum
Which types of invasion is basal cell carcinoma most likely to exhibit?
Perineural or vascular
What is Bowen’s disease?
Pre-cancerous stage of **squamous cell carcioma**
Which type of skin cancer is most likely to become invasive?
Squamous cell carcinoma
What is the fancy name for a mole?
Benign junctional naevus
Which type of skin cancer demonstrates upward migration of melanocytes?
Malignant melanoma
A lump on the upper lip may be due to which type of cancer?
Metastatic renal cell carcinoma
Describe the layers of the skin
What is parakeratosis?
Increased nuclei in S. corenum (when there shouldn’t be)
What s acanthosis?
^ in stratum spinosum
what is acantholysis?
decrease in cohesions between keratinocytes
What is spongiosis?
intercellular oedema
*(*this is what you get in eczema= fluid buildup between the keratinocytes*
define lentiginous
Lentiginous – linear pattern of melanocyte proliferation within epidermal basal cell layer
(reactive or neoplastic)
define lichenoid
sheeny plaque
what does psoriaform mean?
thickened
characteristic feature of eczema rash
ITCHY
what is eczema also called?
dermatitis
what are the 3 types of eczema/dermatitis?
atopic dermatitis
contact dermatitis
seborrheic dermatitis
–all have the same histology but different aetiology
Histology of ALL dermatitis
ACUTE: ● Spongiosis ● Inflammatory infiltrate in
dermis ● Dilated dermal
capillaries
CHRONIC: ● Acanthosis ● Crusting, scaling
**so acutely affects the dermis (hence dermatitis…) and then chronically affects the epidermis as well
distribution of eczema in infants and older people
infants: face, scalp
older: flexural areas
what is a potential clinical feature of chronic eczema?
lichenification
Clinical features of contact dermatitis
Type IV hypersensitivity – e.g. to nickel, rubber Erythema, swelling, pruritis Commonly affects ear lobes and neck (from jewellery), wrist (leather watch straps), feet (from shoes)
**tends to present more so in adults than children, as you need repeated exposure to the trigger for contact dermatitis to develop (from clinic)
What is seborrheic dermatitis?
Inflammatory reaction to a yeast - Malassezia
Infants: cradle cap (large yellow scales on scalp)
Young adults: mild erythema, fine scaling, mildly
pruritic- affects face, eyebrow, eyelid, anterior chest, external ear
What is psoriasis?
Common chronic inflammatory dermatosis with well-demarcated red scaly plaques
Most common form of psoriasis?
chronic plaque psoriasis
description and distribution of chornic plaque psoriasis
salmon pink plaques with silver scale affecting extensor aspects of knees, elbows and scalp.
Key signs in psoriasis
Auspitz sign
Koebner phenomeon
AK
What is auspitz’s sign?
rubbing the lesions causes pin-point bleeding
*positive in psoriasis*
what is koebner phenomenon?
lesions form at sites of trauma
What is the key feature of cells within a proriatic plaque?
increased proliferation rate
histology of psoriasis (x5)
- parakeratosis - increase in nuclei within the stratum corneum (bc of increased proliferation)
- loss of granular layer (maybe bc of increased proliferation?)
- clubbing of rete ridges
- test tubes in a rack appearance
- munro’s microabscesses
what type of hypersenstiivty reaction is psoriasis?
type 4 T-cell mediated
Forms of psoriasis
- chronic plaque psoriasis
- flexural psoriasis
- guttate psoriasis
- erythrodermic/pustular psoriasis
What is flexural psoriasis?
seen later in life, usually groin, natal cleft and sub-mammary areas
**think intimate areas**
what is guttate psoriasis?
“rain-drop” plaque distribution, often in children, usually seen 2 weeks
post-Strep throat
what is erythrodermic/pustular psoriasis?
severe widespread disease, often systemic symptoms,
can be limited to hands and feet = palmo-plantar psoriasis
Associated features of prosiasis
- Nail changes (PSO- PSOriasis):
o Pitting
o Subungual Hyperkeratosis
o Onycholysis
- Arthritis (5-10%)
What is lichen planus?
think Ps
Lesions are “pruritic, purple, polygonal, papules and plaques” with a mother-of-pearl sheen, and fine white network on their surface called Wickam’s striae
**wickam’s striae are usually seen in the oral manifestation of this**
What do you see Wickam’s striae in?
Lichen planus
Where do you get lichen planus?
Inner surface of wrists
Can also affect oral mucous membrane- lacy appearance
Lichen planus histology
hyperkeratosis with saw-toothing of rete ridges and basal cell degeneration
(saws are plain??)
**contrast with psoriasis - clubbing of rete ridges
Type of lesion in erythema multiforme
annular target lesions
pleimorphic lesions
combination of macules, papules, urticarial weals, vesicles, bullae and petechiae
Where do you get erythema multiforme?
Extensor surfaces of hands and feet
causes of erythema multiforme
1) infections
- hsv
- mycoplasma
2) drugs- SNAPP
Sulphonamides (trimethoprim, sulfamethoxazole)
NSAIDS
Allopurinol
Penicillin
Phenytoin
What is steven john syndrome an extreme version of?
erythema multiforme
What are the 3 bullous diseases?
- dermatitis herpetiformis
- bullous pemphigoid
- pemphigus vulgaris
Dermatitis herpetiformis: pathophysiology
Associated with coeliac
IgA Abs bind to basement membrane
Itchy vesicles on extensor surfaces of→ elbows, buttocks
subepidermal bullae
Clinical features of dermatitis herpetiformis
itchy vesicles
on extensor surfaces of elbows, buttocks
histology of dermatitis herpetiformis
Microabscesses which coalesce to form subepidermal bullae
Neutrophil & IgA deposits at tips of dermal papillae
Pathophsyiology of bullous pemphigoid
Clinical features of bullous pemphigoid
Large tense bullae on erythematous base. Often on forearms, groin,
and axillae. ELDERLY. Bullae do not rupture as easily as pemphigus.
Histology of bullous pemphigoid
Subepidermal bulla with eosinophils
Linear deposition of IgG along basement membrane
Pathophysiology of pemphigus vulgaris
IgG Abs bind to desmoglein 1 & 3 → INTRAepidermal bulla PemphiguS - Bullae are Superficial
vulgar - easy to burst
vulgar - bind to two proteins (desmoglein 1 & 3); 13 = unlucky
What is Nikolsky’s sign +ve?
Intra-epidermal lesions such as pemphigus vulgaris
**when you apply lateral pressure to the blister the epidermis comes off**
clinical features of pemphigus vulgaris
Bullae are easily ruptured –> raw red surface. Found on skin AND
mucosal membranes. Nikolsky’s sign +ve. Mucosal involvement.
***pemhigoid does not have mucosal involvement***
histology of pemphigus vulgaris
Intraepidermal bulla
Netlike pattern of intercellular IgG deposits
Acantholysis
What is a benign epidermal cutaneous neoplasm?
seborrheic keratosis
What are the premalignant cutaneous neoplasms?
actinic keratosis
keratocanthoma
bowen’s disease
what is actinic keratosis?
Rough, sandpaper like texture, scaly lesions on sun-exposed areas
Histology of solar keratosis
SPAIN - sunny in spain
Solar elastosis
Parakeratosis
Atypia/dysplasia
Inflammation
Not full thickness
What is keratocanthoma?
Rapidly growing dome shaped nodule which may develop a necrotic, crusted
centre. Grows over 2-3 weeks and clears spontaneously
**so kinda looks like BCC but regresses spontaneously whereas BCC would be growing??**
What condition has similar histology to keratocanthoma?
SCC- difficult to differentiate
What is bowen’s disease?
Intra-epidermal squamous cell carcinoma in situ
Flat, red, scaly patches on sun-exposed area
Histology of bowen’s disease
Full thickness atypia/dysplasia (unlike actinic keratosis - not full thickness)
Basement membrane intact - not invading the dermis
what are the main malignant epidermal skin tumours (i.e. tumours of keratinocytes)
squamous cell carcinoma
basal cell carcinoma
What is squamous cell carcinoma?
Histology of squamous cell carcinoma
What is a basal cell carcinoma?
Histological features of basal cell carcinoma
What are the benign melanocytic tumours?
Benign – melanocytic nevi (=moles). They can be junctional, compound or intradermal.
Histology of malignant melanoma
atypical melanocytes; initially grow horizontally in epidermis (radial growth phase);
then grow vertically into dermis (vertical growth phase); vertical growth produces “buckshot appearance” (=Pagetoid cells)
**starting climbing stairs- horizontal along corridor then vertical**
Important prognostic factor in melanoma
Breslow thickness
Subtypes of melanoma
- lentigo maligna melanoma
- superficial spreading malignant melanoma
- nodular malignant melanoma
- acral lentiginous melanoma
what is lentigo maligna melanoma?
occurs on sun exposed areas of elderly
caucasians, flat, slowly growing black lesion
what is superficial spreading malignant melanoma?
irregular borders with variation in colour
what is nodular malignant melanoma?
can occur on all sites, more common in the
younger age group.
what is acral lentiginous melanoma?
occurs on the palms, soles and subungual areas
acral = extremities
lentiginous = freckled
which melanoma is more common in young ppl?
nodular malignant melanoma
SJS vs TEN
SJS - <10% of body surface area
TEN - >30% body surface area
*also: SJS caused by infections and drugs; TEN usually just caused by drugs*
What sign is positive in SJS and TEN?
Nikolsky’s sign positive
i.e. involves the epidermis
Which drugs can cause SJS and TEN?
Sulfonamide antibiotics
Anticonvulsants
Presentation of pityriasis rosea
Salmon pink rash appears first (=herald patch) followed by oval macules in Christmas tree distribution.
- Appears after viral illness.
- Remits spontaneously
most common skin cancer
bcc
