Inflammatory skin pathology and skin tumours Flashcards
1
Q
Eczema/Dermatitis stages
A
Clinically 3 stages:
- Acute dermatitis = Skin red, weeping serous exudate +/- small vesicles
- Subacute dermatitis = Skin is red, less exudate, itchier, crusting
- Chronic dermatitis = Skin thick and leathery, secondary to scratching
2
Q
Eczema/Dermatitis histology
A
- Spongiosis = = intercellular oedema within epidermis
- Chronic inflammation – predominantly superficial dermis
3
Q
Atopic eczema
A
- Usually starts in childhood, Often FH and associated with asthma and allergic rhinitis
- Type 1 hypersensitivity reaction to allergen
4
Q
Contact irritant dermatitis
A
- Direct injury to skin by irritant; affects anyone in contact with irritants e.g. acid, detergent
5
Q
Contact allergic dermatitis
A
- Affects those with hypersensitivity to irritant; combines with epidermal proteins to become immunogenic; e.g. nickel, dyes, rubber
6
Q
Dermatitis of unknown aetiology
A
- Seborrheic dermatitis – affects areas rich in sebaceous glands – scalp, forehead, upper chest
- Nummular dermatitis – coin shaped lesions
7
Q
Psoriasis definition
A
- 1-2% of population
- Well defined, red oval plaques on extensor surfaces (knees, elbows, sacrum)
- Fine silvery scale
- Auspitz sign = small bleeding points after removal of scale layers
o+/- pitting nails. +/- sero-negative arthritis - Cancer – increased risk of non-melanoma skin cancer
8
Q
Psoriasis histology
A
- Psoriasiform hyperplasia
- Regular elongated club shaped rete ridges
- Thinning of epidermis over dermal papillae
- Collection of neutrophils in scale – Munro micro-abscesses
9
Q
Psoriasis aetiology
A
- Genetic – FH: multiple loci e.g. PSORS gene in MHC of Chromosome 6p2
- Environmental – infection, stress, trauma, drugs
10
Q
DLE =
A
- Discoid lupus erythematosus – skin only
11
Q
SLE =
A
- Systemic–visceral disease
- Butterfly rash on cheeks and nose
12
Q
Lupus Erythematosus
A
- Red scaly patches on sun-exposed areas, scalp involvement
- Autoimmune disorder primarily affecting connective tissue
- Histology:
Thin atrophic epidermis with thickened basement membrane
13
Q
Dermatomyositis
A
Symptoms:
- Peri-ocular oedema and erythema (Heliotropic rash)
- Erythema in photosensitive distribution
- Myositis – proximal muscle weakness - can check for CK
- 25% associated with underlying visceral cancer
14
Q
Bullous pemphigoid
A
- Formation of fluid filled blisters
- Sub-epidermal
- Ends in D = deep
- Autoantibodies to glycoprotein in basement membrane. Destruction causes blister formation which do not rupture
- Elderly
- Can be localised or extensive disease
15
Q
Dermatitis Herpetiformis
A
- Small intensely itchy blisters on extensor surfaces
- Often young patients - associated with coeliac disease
- IgA deposition in dermal papillae on immunofluorescence
- Histology – neutrophil micro-abscesses in dermal papillae – sub-epidermal bulla
16
Q
Basal Cell Carcinoma
A
- Commonest malignant tumour of skin
- Aetiology = sun exposure, radiotherapy, Gorlin’s syndrome
Clinically: - Early – nodule
- Late – rodent ulcer
- Morphoeic BCC = ill-defined and infiltrative
- Histology - islands of basaloid cells
17
Q
Squamous cell carcinoma aetiology
A
- UV irradiation
- Radiotherapy
- Hydrocarbon exposure
- Chronic scars/ulcers (SCC arises with these)
- Immunosuppressed – renal transplant patients at increased risk
- Drugs – e.g. BRAF inhibitors for melanoma
18
Q
Squamous cell carcinoma features
A
- Clinically - nodule with ulcerated crusted surface
- Histology - invasive islands wit trabeculae of squamous cells with cytological atypia
19
Q
Acitinic Keratosis
A
- Pre-malignant disease of SCC
- Dysplasia to squamous epithelium
- Very common on chronic sun exposed sites
- Scaly lesion with erythematous base
20
Q
Melanocyte tumours
A
- Melanocytes derive from neural crest
- Function – produce melanin which is transferred to epidermal cells to protect the nucleus from UV radiation
- Give rise to naevi/moles (benign) and melanoma (malignant)
21
Q
Naevi/moles
A
- Local benign collections of melanocytes
Several types: - Superficial – congenital or acquired
- Deep – blue naevi (Mongolian spot)
22
Q
Atypical mole syndrome
A
- Families with increased incidence of melanoma
- Multiple clinically atypical moles
- Histologically atypical/ dysplastic
- Increased risk of developing melanoma
23
Q
Melanoma risk factors
A
- Sun exposure – especially short intermittent severe exposure
- Race – celtic with red hair, blue eyes, fair skin who tan poorly most at risk.
- Family history – atypical mole syndrome
- Giant congenital naevi
24
Q
Lentigo Maligna Melanoma
A
- Face, elderly people, slow growing, flat, pigmented patch
- Proliferation of atypical melanocytes along basal layer of epidermis
- Skin also shows signs of chronic sun damage
- Late in disease, melanocytes may invade dermis which can metastasise
25
Q
Acral Lentiginous Melanoma
A
- Palms and soles; commonest form in afro-Caribbean people
- Forms enlarging pigmented patch
- No marked sun damage
26
Q
Superficial spreading melanoma
A
- Commonest type of melanoma in UK
- Early – flat macule
- Late – black/blue nodule
- Histology – proliferation of atypical melanocytes which invade epidermis and dermis
- Genetics – often BRAF mutations targets for anticancer agents.
27
Q
Nodular melanoma
A
- Starts as pigmented nodule +/- ulceration
- Poor prognosis
- Histology – invasive atypical melanocytes invade dermis to produce nodules of tumour cells
28
Q
Prognosis of melanoma
A
- Most important factor = Breslow thickness
- Measure on microscope from granular layer of epidermis to base of tumour
- Back, arms, neck, scalp = poorer prognosis
- Sentinel node - first to be drained and tested
29
Q
Treatment of melanoma
A
- Surgery – excise primary and lymph nodes if sentinel node is +ve
- BRAF inhibitors – 60% of melanomas have B-RAF gene mutations
30
Q
Breslow thickness thresholds
A
Breslow thickness (mm) 5yr survival % <1 91-95 1-2 75-90 2-4 60-75 >4 45-60
