CP10-2 Inflammatory Skin Tumours Flashcards
What cells give us skin pigment and protect us from UV damage?
Melanocytes
What are the 5 main layers if the epidermis from top to bottom?
Keratanised squamous
Granule cell layer
Prickle cell layer
Basal cell layer
Basal lamina
What are examples of non infectious inflammatory skin diseases?
Dermatitis/psoriasis
Blistering
Connective tissue diseases e.g. lupus
Skin lesions as signs of systemic disease
Skin lesions caused by metabolic disorders
What are s9me major tissue reaction patterns?
Lichenoid
Psoriasiform
Spongiotic
Vesiculobullous
What are examples of inflammatory skin diseases with lichenoid reaction patterns?
Lichen planus
Lupus erythematous
Dermatomyositis
What is an example of inflammatory skin diseases with a psoriasiform reaction pattern?
Psoriasis
What is an example of an inflammatory skin diseases with a spongiotic reaction pattern?
Eczema
What are some examples of inflammatory skin diseases with vesiculobullous reaction patterns?
Pemphigoid
Pemphigus
Dermatitis herpetiformis
What is the epidemiology of eczema/dermatitis?
5% if children in UK
What are the three stages of dermatitis/eczema?
1 - Acute dermatitis - skin is red and weeping serous exudate +/- small vesicles
2 - subacute dermatitis - skin is red, producing less exudate with pruritus and crusting
3 - chronic dermatitis - skin becomes thick and leathery secondary to scratching
What microscopy findings are found in eczema/dermatitis?
Spongiosis (intracellular oedema with epidermis)
Chronic inflammation - predominantly on superficial dermis
Epidermal hyperplasia and hyperkeraosis - becomes more marketed as dermatitis changes from acute to chronic
What is atopic eczema?
A type 1 hypersensitivity reaction to allergens, often associated with asthma and hay fever. Usually starts in childhood but occasionally can present in adulthood. Associated with family history.
What is contact irritant dermatitis?
When direct injury to skin by an irritant causes dermatitis e.g. acid, strong detergent etc…
What is contact allergic dermatitis?
A delayed type 4 hypersensitivity reaction where an irritant e.g. nickel, dyes, rubber, combine with epidermal proteins to become immunogenic.
What types of dermatitis have an unknown aetiology?
Seborrhoeic dermatitis
Nummular dermatitis
What is seborrhoeic dermatitis?
Dermatitis in areas rich in sebaceous glands e.g. scalp, forehead and upper chest
What is nummular dermatitis?
Dermatitis characterised by coin shaped lesions
What is the epidemiology of psoriasis?
1- 2% of population
What are symptoms and signs of psoriasis?
Well defined, red oval plaques on extensor surfaces (knees, elbows, sacrum)
Fine silvery scale
Auspitz sign - removal of scale causes small bleeding point
+/- pitting nails
+/- sero-negative arthritis
Potentially oral manifestations.
How does psoriasis appear under the microscope?
With psoriasiform hyperplasia which is characterised by:
- regular elongated club shaped rate ridges
- thinking of epidermisover dermal papillae
-parakeratotic scale (contain nuclei)
- munro microabcesses (collections of neutrophils in the scale)
What is the pathogenesis of psoriasis?
Clinical and microscopic features reflecting massive cell turnover which is idiopathic but possibly autoimmune where a trigger factor leads to a dysfunctional immune reaction.
What increases your risk of psoriasis?
Genetics - PSORS genes
Environmental triggers e.g. infection, stress, trauma, drugs
What comorbidities are associated with psoriasis?
Arthyropathy
Psychological affects
CVD
Increases risk of non-melanoma skin cancer, e.g. BCC, and lymphoma
Where are lichen planus rashes found?
On flexor surfaces
Mucous membranes e.g. oral cavity
Genitals
What is lichen planus?
An idiopathic inflammatory skin condition potentially caused by a type 4 hypersensitivity reaction which affects adults and is often self limiting. It usually lasts around 1-2 years.
What is lupus erythematous?
An autoimmune disorder which primarily affects connective tissues of the body as autoantibodies are directed at various tissues.
What is lupus which only affects the skin known as?
Discoid lupus erythematous (DLE)
What skin symptoms do patients with lupus erythematous present with?
Red scaly patches on sun exposed skin +/- scarring
Scalp involvement causing alopecia
What skin symptom is characteristic of SLE?
Butterfly rash on nose and cheeks
How does LE appear microscopically?
Skin has a thin atrophic epidermis with inflammation and destruction of adnexal structures
What is dermatomyositis?
Peri-ocular oedema and erythema in a photosensitive distribution with myositis and proximal muscle weakness.
What rash is characteristic of dermatomyositis?
Heliotropic rash heliotropic rash
What is associated with dermatomyositis in 25% of affected adults?
Underlying visceral cancer
How does dermatomyositis appear microscopically?
Similarly to lupus erythematous + a lot of dermal mucin and negative for IMF
What are bullous diseases?
Diseases which result in formation of fluid filled blisters
What are the two types of bullous skin disease?
Pemphigus
pemphigoid
What is the difference between pemphigus and pemphigoid bullous?
Pemphigus = intra-epidermal bulla with intracellular immunofluorescence
Pemphigoid = sub-epidermal bulls with immunofluorescence in the basement membrane.
What is meant by the term pemphigus disorders?
Disorders characterised by loss of cohesion between keratinocytes resulting in intraepidermal blisters which are fragile so rupture easily. They can be extensive and may involve mucous membranes. Can be detected by immunofluorescence.
What is the pathogenesis of pemphigus disorders?
Autoantibodies are directed against intercellular material resulting in bulla formation.
What are bullous pemphigoid diseases?
Diseases characterised by supepidermal blisters which tend to be large and tense so do not rupture easily. They are found in the elderly and can be localised or extensive.
What is the pathogenesis of bullous pemphigoid diseases?
Autoantibodies attack the glycoproteins in the basement membrane.
What is dermatitis herpetiformis?
Small intensely itchy blisters which form on extensor surfaces due to IgA deposition in dermal papillae resulting in neutrophil microabcesses forming here - often in young patients. It is associated with coeliac disease.
What are some skin lesions which are signs of systemic diseases? Which diseases are they a sign of?
Dermatomyositis = visceral cancer
Dermatitis herpetiformis = coeliac disease
Acanthosis nigricans = internal malignancy
Necrobiosis lipoidica = diabetes mellitus
Erythema nodosum = infections elsewhere esp. lungs
What are basal cell carcinomas?
The commonest malignant skin tumour that appears on sun exposed skin, or secondary to radiotherapy, which rarely metastases.
What increases risk of basal cell carcinomas?
Having pale skin
Having had radiotherapy
Immunosuppression
Gorlin’s disease
How do basal cell carcinomas look on the skin
In early stages as a nodule but later become an ulcer (if has rolled edge called rodent ulcer)
How do BCC appear under the microscope?
As a tumour composed of islands of basaloid cells with peripheral palisade.
What increases your risk of having a squamous cell carcinomas?
UV radiation exposure
Radiotherapy
Hydrocarbon exposure e.g. if you are a chimney sweep
Immunosuppression
Having chronic scars/ulcers e.g. Marjolins ulcer
Drugs e.g. BRAF inhibitors
How do SCC present clinically?
How do they look microscopically?
With an ulcerated nodule with a crusted surface.
Appears microscopically with invasive islands and trabeculae of squamous cells with cytological atypia
What makes a SCC at higher risk of metastasising?
If on lip, ear or perineum
If >2 cm in diameter or >6 mm thick
If high grade
What is actinic keratosis?
A pre-malignant disease to SCC where there is dysplasia in the squamous epithelium causing a scaly lesion with an erythematous base which may spontaneously resolve or rarely progress to invasive diseases
Where do melanocytes derive from?
Neural crest
How do melanocytes protect cells from UV radiation?
By producing melanin which is transferred to epidermal cells to protect their nucleus
What tumours develop from melanocytes?
Malignant melanomas
Benign naevi (moles)
What are the main types of naevi?
Superficial - congenital or acquired
Deep - blue naevi and Mongolian spots
What are naevi?
Local benign collection of melanocytes
What melanocyte tumours are found on babies?
Giant congenital naevi
What is atypical mole syndrome?
Multiple clinically atypical moles which are atypical and dysplastic naevi, associated with family history of increased incidence of melanomas.
How can naevi and melanomas be differentiated?
Naevi = symmetrical, even borders, uniform colour and diameter <6 mm
Melanomas = asymmetrical, uneven borders, colour variations and diameter >6 mm
What increases your risk of developing a melanoma?
Short intermittent sever sun exposure
Race -fair complexion e.g. Celtic with red hair and blue eyes - rare in dark skinned people
Family history
If have giant congenital naevi
What is the most common type of melanoma in Britain?
Superficial spreading melanoma
How do superficial spreading melanomas present clinically?
In early stages as a flat macule but in late stages appears as a blue/black nodule
How do superficial spreading melanomas appear under the microscope?
With proliferation of atypical melanocytes which invade the epidermis, with a pagetoid spread, and dermis.
What mutation is being targeted for anti cancer agents for melanomas?
BRAF
What is nodular melanoma?
A pigmented nodule +/-ulceration with a poor prognosis.
How do nodular melanomas appear microscopically?
With invasive atypical melanocytes which invade the dermis to produce nodule of tumour cells.
What is lentigo maligna?
A tumour of the face found in elderly people which appears as a slow growing, pigmented patch. In later stages the melanocytes may invade the dermis to form a lentigo maligna melanoma with potential to metastasise.
How does lentigo maligna appear microscopically?
As proliferation of atypical melanocytes along the basal layer of the epidermis with signs of chronic sun damage on the skin.
What is acral lentigenous melanoma?
Melanoma which appears as an enlarging pigmented patch on the palms and soles, occasional subungal (under the nails), commonly in Afro-caribbeans .
How do acral lentigenous melanomas look microscopically?
Similarly to lentigo maligna except there is no marked sun damage.
What is used to asses prognostic factors of melanomas?
Breslow thickness - measured under microscope from granular layer of epidermis to base of tumour - as thickness goes up, 5 year survival % goes down
Other than breslow thickness, what prognostic factors are used for melanomas?
Site of melanoma - BANS (back, posterior upper arms, neck and scalp) have poorer prognosis
Ulceration = poorer prognosis
Presence of satellites/in transits
Presence of sentinel nodes - removal of sentinel and surrounding lymph nodes increases prognosis
How are melanomas treated?
Surgery to excise tumour + lymph nodes of sentinel lymph node is positive
BRAF inhibitors to target mutation in B-raf gene (mutations usually confer resistance)
Immunotherapy for sustained remission
