Dermatology - Skin cancer Flashcards
What is basal cell carcinoma? How does it present?
Basal cell carcinoma (BCC) is one of the three main types of skin cancer. Lesions are also known as rodent ulcers and are characterised by slow-growth and local invasion. Metastases are extremely rare. BCC is the most common type of cancer in the Western world.
Features:
- many types of BCC are described. The most common type is nodular BCC, which is described here
- sun-exposed sites, especially the head and neck account for the majority of lesions
- initially a pearly, flesh-coloured papule with telangiectasia
- may later ulcerate leaving a central ‘crater’
What is the cause of BCC?
Risk factors include UV exposure, history of frequent or severe sun burn in childhood, skin type I (always burns, never tans), increasing age, male sex, immunosuppression, previous history of skin cancer, and genetic predisposition.
What are the management options for BCC?
Management options:
- surgical removal: first line, allows histological examination of tumour margins
- curettage
- cryotherapy
- topical cream: imiquimod, fluorouracil
- radiotherapy: when surgery is not appropriate
Mohs micrographic surgery (i.e. excision of the lesion and tissue borders are progressively excised until specimens are microscopically free of tumour).
What is squamous cell carcinoma (SCC)?
This is a locally invasive malignant tumour of epidermal keratinocytes or its appendages, which has the potential to metastasise.
Risk factors include:
- excessive exposure to sunlight
- actinic keratoses and Bowen’s disease
- immunosuppression e.g. following renal transplant
- smoking
- long-standing leg ulcers (Marjolin’s ulcer)
How does SCC present? How are they treated?
Presents as keratotic (e.g. scaly, crusty), ill defined nodules which may ulcerate.
Management includes:
- surgical excision: treatment of choice
- Mohs micrographic surgery: may be necessary for ill-defined, large, recurrent tumours
- radiotherapy: large, non resectable tumours
What is Bowen’s disease?
Bowen’s disease is a type of intraepidermal squamous cell carcinoma. More common in elderly females. There is around a 3% chance of developing invasive skin cancer
Features:
- red, scaly patches
- often occur on the lower limbs
What is erythema ab igne?
Erythema ab igne is a skin disorder caused by over exposure to infrared radiation. Characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia (look like fishnets!). A typical history would be an elderly women who always sits next to an open fire.
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
What is malignant melanoma?
This is an invasive malignant tumour of the epidermal melanocytes, which has the potential to metastasise.
Risk factors include:
- excessive UV exposure
- type I skin
- history of multiple moles or atypical moles
- family history of previous melanoma
How does malignany melanoma present?
The "ABCDE symptoms" rule:
Asymmetrical shape
Border irregularity
Colour irregularity
Diameter >6 mm
Evolution of lesion (e.g. change in size and/or shape)
Symptoms (e.g. bleeding, itching)
It is more common in the legs in women and the trunk in men.
Outline the different types of melanoma?
1) Superficial spreading melanoma - common on the lower limbs, in young and middle aged adults; related to intermittent high intensity UV exposure
2) Nodular melanoma - common on the trunk, in young and middle aged adults; related to intermittent high intensity UV exposure
3) Lentigo maligna melanoma - common on the face, in elderly population; related to long term cumulative UV exposure
4) Acral lentiginous melanoma - common on the palms, soles and nail beds, in elderly population; no clear relation to UV exposure
How should malignant melanoma be managed?
Surgical excision of suspicious lesions is definitive treatment. The lesion should be removed completely, as incision biopsy can make subsequent histopathological diagnosis difficult.
Pathology determines whether further re-excision of margins is required. This is related to the Breslow thickness:
- Lesions 0-1mm thick 1cm
- Lesions 1-2mm thick 1- 2cm (Depending upon site and pathological features)
- Lesions 2-4mm thick 2-3 cm (Depending upon site and pathological features)
- Lesions >4 mm thick 3cm
Lower Breslow thickness the better the 5 year prognosis.
What determines the prognosis of malignant melanoma?
Recurrence of melanoma based on Breslow thickness (thickness of tumour): <0.76mm thick – low risk, 0.76mm-1.5mm thick – medium risk, >1.5mm thick – high risk
5-year survival rates based on the TNM classification (primary Tumour, regional Nodes, Metastases): stage 1 (T <2mm thick, N0, M0) - 90%, stage 2 (T>2mm thick, N0, M0) – 80%, stage 3 (N≥1, M0) – 40- 50%, and stage 4 (M ≥ 1) – 20-30%
