Skin Cancer Flashcards
What are the keratinocyte skin cancers, and why are they classed as that?
Basal Cell Carcinomas (BCC)
Squamous Cell Carcinomas (SCC)
They arise from keratinocytes
What cells do melanomas arise from?
Melanocytes
What are melanocytes?
The pigment forming cells scattered along the basal layer of the epidermis
Where do melanocytes migrate from?
Migrate from the neural crest
Which are more likely to metastasise: melanoma or keratinocyte skin cancers?
Melanomas
What clinical features shows that a melanoma has metastasised?
Micronodules - little black dots around the main melanoma
What factor correlates with the prognosis of a melanoma, and how is this measured?
Tumour depth
Breslow thickness - AKA the measurement of depth of the melanoma from the surface of the skin to the deepest point of the tumour
What factors are used to evaluate whether a pigmented nodule is a melanoma?
Asymmetry Border Colour Diameter Evolution
How do basal cell carcinomas present?
Slow growing lump or ulcer Painless Shiny appearance Telangectasia Central ulceration
In what way can BCCs spread?
Locally - very rarely metastasise
What are the different types of BCC?
Superficial
Nodular or nodulocystic
Infiltrative or morphemic
Pigmented
What do superficial BCCs look like?
Scaly plaque resembling dermatitis
How do squamous cell carcinomas present?
Kyperkeratotic lump or ulcer
On sun-damaged skin
Fast growing
May be painful and/or bleed
What is a keratoacanthoma?
A self-resolving SCC
What are high risk sites for SCC?
Ear
Lip
Scalp
Where can SCCs commonly metastasise to?
Lymph nodes
Bone
What are the main risk factors for skin cancer?
Sun exposure Family history Genetic susceptibility Immunosuppression Environmental carcinogens (smoking, coal tar etc)
What are examples of genetic conditions that predispose to skin cancer?
Xeroderma pigmentosum
Albanism
What is a benign skin tumour?
Seborrheic keratosis
What is seborrheic keratosis?
Benign proliferation of epidermal keratinocytes
What is the clinical presentation of seborrheic keratosis?
‘Stuck-on’ appearance with a greasy keratitis surface
What may an eruptive appearance of many keratotic lesions indicate?
Internal malignancy
What are the precursors of squamous cell carcinoma?
Bowen’s disease
Actinic keratosis
Viral lesions
What is Bowen’s disease?
Scaly patch/plaque
Especially on legs
Females mostly
Irregular border
What is actinic keratosis?
Variable epidermal dysplasia
Very common
Sun exposed skin, especially head/neck, hands
What are rare presentations of SCC?
Chronic leg ulcers
Sites of burns, sinuses
Chronic lupus vulgaris
Xeroderma pigmentosum
What are adverse prognosis features of SCC?
Breslow thickness >4mm with poor differentiation
Lymphatic/vascular space invasion
Periurnal spread
Some sites - scalp, ear, nose
What are the types of melanoma?
Superficial spreading
Acral or mucosal lentiginous
Lentigo maligna melanoma
Nodular
What is different about nodular melanomas?
No rapid growth phase, only vertical growth phase
What sites do melanomas metastasise to, and by which type of spread?
Skin/soft tossue Heart Lungs GI tract Liver Brain Haematological spread
What is the technical term for freckles?
Ephelides
What are ephelides?
A patchy area of increase in melanin pigmentation after UV exposure
What are actinic lentigenes better known as?
Age or liver spots
What are actinic lentigines?
Areas of increase in melanin and basal melanocyte population related to UV exposure
What are melanocytic naevi?
A broad range of benign pigmented lesions
What are the different types of melanocytes naevi?
Congenital Usual type Dysplastic Spitz Blue
What are classed as small, medium and giant congenital naevi?
Small - <2cm
Medium - >2cm, <20cm
Giant - >20cm
What is the risk of congenital naevi progressing to melanoma?
Larger lesions have 10-15% risk
What are usual type naevi?
Naevi acquired during infancy when the melanocyte:keratinocyte ratio breaks down at a number of cutaneous sites
What is the process of development of a usual type naevi?
Juntional phase - clusters of melanocytes form at the derma-epidermal junction, melanocytes proliferate
Compound phase - junctional clusters at the demo-epidermal junction and groups of cells in the dermis
Intradermal phase - all junctional activity has ceased, entirely dermal
What do dysplastic naevi look like?
Generally >6mm in diameter
Variegated pigment
Border asymmetry
What are sporadic dysplastic naevi?
Not inherited
One to several atypical naevi
Risk of malignant melanoma slightly raised
What are familial dysplastic naevi?
Strong family history of melanoma Autosomal inheritance High penetrance Multiple atypical naevi Lifetime risk of melanoma up to 100%
How are dysplastic naevi diagnosed histologically?
Atypical architecture and cells
Host reaction - fibrosis and inflammation
Epidermis not affected
What are halo naevi?
Have a peripheral help of depigmentation
Show inflammatory regression
Overrun by lymphocytes
What are blue naevi?
Entirely dermal
Consist of pigment-rich dendritic spindle cells
What are spitz naevi?
In people <20
Look like melanoma but most benign
Consist of large spindle and/or epithelioid cells
Pink appearance due to dilated capillaries
