Basal cell carcinoma Flashcards
Define basal cell carcinoma.
Commonest form of skin malignancy, related to sun exposure.
BCC has also been known as basal cell epithelioma, reflecting the fact that this neoplasm infrequently metastasises. It can be locally aggressive, but rarely metastasises.
What is the pathophysiology of BCC?
- Basal cells grow in well-defined aggregates invading the dermis with the outer layer of cells arranges in palisades.
- Probably p53 gene mutation and aberrant activation of sonic hedgehog signalling cascade.
- Mitotic and apoptotic bodies seen
- Growth rate is slow, but steady and insidious
- Does not metastasize but has ability to invade and destroy local tissues.
What are the risk factors for BCC?
- UV radiation - mostly 290-320 nm wavelength UV (sunburn wavelength)
- sun exposure
- X-ray exposure
- arsenic exposure - in contaminated water
- xeroderma pigmentosum
- basal cell naevus syndrome (Gorlin-Goltz syndrome)- autosomal dominant inheritance
- transplant patients
What is xeroderma pigmentosum?
An inborn error of DNA-repair mechanisms predisposes patients who suffer from this genetic defect to develop early skin ageing, innumerable BCCs, SCCs, and sometimes a melanoma
What are the signs and symptoms of BCC?
- Papules associated with telangiectasias
- Plaques, nodules, tumours with rolled borders
- Small crusts and non-healing wounds
- Non-healing scabs
- Pearly papules or plaques
All characteristic of BCC.
What are the clinical features of this lesion? What is it?
BCC - The lesion is a shiny pearly nodule with prominent blood vessels on the surface called telangiectasia.
How is BCC diagnosed?
Biopsy for dermatohistopathology - shave or punch biopsy. Or diagnosis and treatment at same time if lesion is small.
What are some high risk areas for complication of basal cell carcinoma?
- Around the eyes
- Nasolabial folds
- Around the ear canal
- Posterior auricular sulcus
BCC at embryological fusion lines may invade deeply making the risk of recurrence higher.
Mohs excision is used here to ensure clear margins.
This non-healing solitary lesion (image below) has been slowly expanding on the trunk of a 70-year-old man for 3 years. What is the diagnosis?
- Superficial BCC
- Psoriasis
- Tinea corporis
- Bowens disease
Superficial BCC
This type of BCC presents as a red scaly plaque. A rolled edge/ pearly border is sometimes discernible.
You might be worried about a melanoma within this lesion - although it could just be blood.
What are these?
TL - Bowen’s disease - early form of skin cancer that is easily treatable. Main sign is red, scaly, patch on the skin. Easy to miss.
BL - SCC
TR - epidermoid cyst - smelly, yellow keratin material would come out if squeezed
BR - dermatofibrome - common benign lesion, usually due to bite or trauma where there is overreaction of the immune system causing hyperpigmenttaion and dimpling if squeezed.
If BCCs don’t metastasise why are they removed?
They cause terrible local destruction - e.g. if on nose you could lose all the cartilage and even bone around it.
What types of BCCs are these?
Is cryotherapy a good treatment for naevi?
Cryotherapy
- Should only be used for benign lesions as it causes destruction of tissue so you have no histology to confirm that the lesion was not malignant
What locations are BCCs dangerous in?
Embryological sites of fusion - nasolabial folds ect. more likely to invade in these areas
Should the patient be instructed to stop his Aspirin 10 days prior to surgery?
Aspirin is routinely stopped prior to skin surgery unless there is a good reason not to in terms of thromboembolic risk.
What are the subtypes of BCC?
Nodular - most common
Superficial - poorly defined margins
Micronodular
Metatypical (BCC with squamous differentiation)
Morpheaform
Infundibulocystic
Mixed
