Skin Cancer Flashcards
Name and describe two benign skin lesions
- Fibro epithelial polyps “skin tags”
* Seborrhoeic warts/keratoses
What two pathways interact to cause skin cancer?
- Direct action of UV on target cells (keratinocytes) for neoplastic transformation via DNA damage
- Effects of UV on the host’s immune system
What are the three main skin cancer types?
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant melanoma
What level of infiltration occurs in a squamous cell carcinoma?
Epidermis
What layer of infiltration occurs in a basal cell carcinoma?
Epidermis and dermis
Explain the pathogenesis of a basal cell carcinoma
- Process of creating new skin cells is controlled by a basal cell’s DNA
- A mutation in the DNA causes a basal cell to multiply rapidly and continue growing when it would normally die
- The accumulating abnormal cells may form a tumour
Which gene mutation may predispose to a basal cell carcinoma?
PTCH
Where is the common site of basal cell carcinoma?
80% found on the head and neck/UV exposed sites
What is the appearance of a nodular basal cell carcinoma?
- Shiny
- Nodule i.e. raised lesion>0.5cm
- Telangectasia/blood vessels
- Often ulcerated centrally
What are the subtypes of basal cell carcinoma?
- Nodular
- Superficial
- Pigmented
- Morphoeic/sclerotic
What is the appearance of a morphoeic/sclerotic basal cell carcinoma?
- Depressed area of skin
* Still shiny with increased blood vessels
What is the gold standard treatment of basal cell carcinoma?
Surgical excision with a 3-4mm margin
What are the treatments for basal cell carcinoma?
- Surgical excision 3-4mm margin
- Curettage and cautery
- Cyrotherapy
- Photodynamic therapy
- Topical imiquimod/ 5- fluorouracil cream
- Mohs micrographic surgery
What cell do squamous cell carcinomas originate from?
Keratinocytes
What are the pre-malignant variants of squamous cell carcinoma?
- Actinic keratoses
* Bowen’s disease
Where do most squamous cell carcinomas present?
- On skin regularly exposed to sunlight or other UV radiation
- Can occur in normal skin or in skin that has been injured e.g. burns or chronically inflamed
What are the risks of metastasis for basal cell carcinomas and squamous cell carcinomas?
- Basal cell carcinoma has a low risk of metastasis
* Squamous cell carcinoma that is a high risk SCC has a 10-30% risk of metastasis (ears and lips are high risk sites)
Describe the appearance of squamous cell caricnomas
- Nodule
- Keratin crust
- Red background
What is the gold standard treatment of squamous cell carcinoma?
Surgical excision with a 4mm margin
What are the treatments for a pre malignant squamous cell carcinoma?
- Topical imiquimod/ 5-fluorouracil cream
- Cryotherapy
- Photodynamic therapy
What is a melanoma?
Malignant tumour of melanocytes
Describe the growth of melanoma
- Radial growth phase
* Then vertical growth
How does melanoma spread?
Via the lymphatics
What determines the prognosis of melanoma?
The depth of presentation
What are the risk factors for the development of melanoma?
- Genetic markers
- Family history
- UV irradiation
- Congenital or multiple atypical nevi
- history of previous melanoma
- Skin type I or II
- High socioeconomic status
- DNA repair defects
- Immunosuppression
What are the staging tools for melanoma
•Clark’s levels and Breslow depth
What is the subtype of melanoma that is on the hands and feet?
Acral mealnoma
What is the subtype of melanoma that occurs under the nails
Subungual melanoma
What is the subtype of melanoma that lacks pigment?
Amelanotic melanoma
What is the precursor of melanoma that tends to present on the head and neck?
Lentigo maligna
What is the precursor of melanoma that can present anywhere on the body?
Melanoma in situ
What is the treatment of melanoma in someone with a Breslow <1mm
Surgical excision with a 1cm margin
What is the treatment of a melanoma with a breslow >1mm?
2cm margin surgical excision
Aside from excision, what is the treatment of melanoma?
- Immunotherapy (ipilimumab)
- Immune check point/MEK inhibitors (trametinib)
- Biologic antibodies e.g. BRAF genetic defects (debrafanib)
What further investigations should be carried out in someone with a diagnosed melanoma?
- Imaging/ scanning: MRI, CT or PET
- Assessment of lymph node/organ spread
- Genetic testing in families if multiple primary melanomas
- Long term follow up of 5 years
Gorlin’s syndrome
- Multiple basal cell carcinomas
- Jaw cysts
- Risk of breast cancer
Brook spiegler syndrome
- Multiple basal cell carcinoma
* Trichoepitheliomas
Gardner syndrome
- Soft tissue tumours
- Polyps
- Bowel cancer
Cowden’s syndrome
- Multiple hamartomas
* Thyroid, breast cancer
