Basal Cell Carcinoma Flashcards
What is the most common type of cancer in the world?
Basal cell Carcinoma
What are the three layers of the skin?
- Epidermis
- dermis
- Hypodermis
In which layer of the skin is the basal layer found?
epidermis
What is the estimated lifetime risk for a BCC in white men?
33-39%
what is the lifetime risk for BCC in white women?
23-28%
Mutations of what two genes are associated with BCCs?
1) PTCH
2) TP53
Give 5 risk factors for basal cell carcinomas:
1) exposure to UV radiation (esp. at a young age)
2) history of skin caner
3) fair skin prone to sunburn
4) prolonged exposure to chemical agents like arsenic
5) Gorlin syndrome
What genetic syndrome associated with a mutation of the PTCH1 gene is associated with basal cell carcinomas?
Gorlin syndrome
What is Gorlin syndrome?
a disease where the PTCH1 gene is mutated, leading to a high risk of BCCs and formation of benign tumours in the heart, brain and ovaries
Where are basal cell carcinomas typically found?
in sun-exposed areas such as the face, forehead and scalp
What are the three types of basal cell carcinoma?
- Nodular
- Superficial
- Morpheaform
What is the most common type of BCC?
Nodular
What is the second most common type of BCC?
Superficial basal cell carcinoma
What is the rarest type of BCC?
Morpheaform basal cell carcinoma
What capillary sign is associated with nodular BCCs?
arborising telangiectasis
Describe the morphology of a nodular BCC:
- pearly shiny nodules with rolled edges
- Often a depressed centre
What is aborising telangiectasias?
tree-like branching capillaries found at the edge of a nodular basal cell carcinoma
Describe the morphology of superficial BCCs:
plaque or patch of well defined scaly pink skin
Describe the morphology of morpheaform BCCs:
poorly defined pale scales that feature linear serpentine vessels
What instrument can be used to better view skin lesions on physical examination?
Dermascope
What is the gold standard diagnostic investigation for BCCs?
biopsy and histological examination
Give 4 types of biopsy that can be used to investigate BCCs:
1) excisional
2) incisional
3) shave
4) punch
What two types of BCC are considered low-risk?
1) nodular
2) superficial
What type of BCC is considered high-risk?
morphoeaform (they can have extensive local spread)
What are 3 histological features of basal cell carcinomas?
- Apoptotic cells
- basophilic aggregations of basaloid keratinocytes with large nuclei and hardly any cytoplasm
- Peripheral palisading of nuclei
What is meant by the histological finding ‘peripheral palisading of nuclei’?
nuclei lining up at the edges of tumours
Give 4 methods for removing low-risk BCCs:
1) complete surgical removal
2) electrodesiccation and curettage
3) cryotherapy
4) photodynamic therapy
Describe electrodesiccation and curettage as a method for removing low-risk BCCs:
a curette is used to scrape the tumour down the dermis and then electrodesiccation applies electricity to denature the layer of the dermis down to the healthy tissue
Give two methods for removing high-risk BCCs:
1) simple resection with radiotherapy
2) Moh’s micrographic surgery
Describe Moh’s micrographic surgery as a method for removing high-risk BCCs:
removal of a BCC where the wound is only closed when microscopy has confirmed the entire cancer has been removed
True or false: having a BCC increases your risk of melanoma
true
