Skin Cancers 2 Flashcards
When is keratinocyte dysplasia/carcinoma common?
- pale skin types
- solar induced UV damage
What are the stages of keratinocyte dysplasia?
- Actinic keratoses
- Bowen’s disease
- Squamous cell carcinoma
- aBasal cell carcinoma
What is actinic keratoses?
Dysplastic keratinocytes
What is Bowen’s disease?
Squamous cell carcinoma in situ
What is squamous cell carcinoma?
Potential for metastasis/ death
What is basal cell carcinoma?
- (Virtually) never metastasises
- Locally invasive
What is the pathogenesis of basal cell carcinoma?
UV radiation
What is the pathogenesis of basal cell carcinoma dependent on?
stroma produced by dermal fibroblasts
What happens in the stroma in basal cell carcinoma (BCC)?
- Cross talk between tumour cells and mesenchymal cells of stroma
- Receptors for PDGF are upregulated in Stroma
- but PDGF is upregulated in tumour cells
What is the activity of BCC like?
proteolytic activity e.g. metalloproteinases and collagenases – degrade pre-existing dermal tissue and facilitate spread of tumour cells
What genes loose function in BCC?
- Loss of function in chromosome 8q (PTCH gene)
- Sonic Hedgehog-Patched signalling pathway
/ SHH signalling is required for growth of established BCCs - p53 mutations are also important – majority are missense mutations that carry a UV signature
Why does squamous cell carcinoma develop?
- UV radiation
- Genetic alterations
What genes make an impact in squamous cell carcinoma?
- P53
- CDKN2A
- NOTCH1 or NOTCH2 (Wnt / β-catenin signalling)
What are the process of squamous cell carcinoma development?
- Normal skin
- Epidermal p53 clone
- Squamous cell dysplasia
- Squamous cell carcinoma in situ
- Invasive squamous cell carcinoma
- Metastasis of squamous cell carcinoma
What is the most common type of skin cancer?
Basal cell carcinoma
How common is BCC compared to keratinocyte carcinomas?
- BCC:SCC 4:1
- Both commoner in pale skin types
- Both more common in men vs women (2-3:1)
- Median age at diagnosis of BCC is 68
What are the risk factors keratinocyte carcinomas?
•UV exposure
- PUVA
•Fair skin
•Genetic syndromes
What are the genetic syndromes that cause keratinocyte carcinomas?
- Xeroderma pigmentosum
- Oculocutaneous albinism
- Muir Torre syndrome
- Nevoid basal cell carcinoma syndrome*
What are the other risk factors of kertinocyte carcinomas?
- Nevus sebaceous
- Porokeratosis
3, Organ transplantation (immunosuppressive drugs) - Chronic non-healing wounds
- Ionising radiation
- Airline pilots - Occupational chemical exposures
- Tar, polycyclic aromatic hydrocarbons,
What are atypical keratinocytes confined to?
epidermis
Where does actinic keratoses develop?
sun-damaged skin - usually head, neck, upper trunk and extremities
What does actinic keratoses look like?
- Erythematous macule or scale or both-> thick papules or hyperkeratosis or both
- Sometimes cutaneous horn
How do you distinguish actinic keratoses from SSC?
sometimes difficult – requiring biopsy
What is the risk of progression from actinic keratoses to SCC?
0.025–16% per year for any single lesion
What is Bowen’s disease?
Squamous cell carcinoma in situ
What does Bowen’s disease look like?
Erythematous scaly patch or slightly elevated plaque
When might Bowen’s disease arise?
de novo or from pre-existing AK
What can Bowen’s disease resemble?
- actinic keratoses
- psoriasis
- chronic eczema
What is the treatment of actinic keratoses and Bowen’s disease?
- 5-fluorouracil cream
- Cryotherapy
- Imiquimod cream
- Photodynamic therapy
- Curettage and cautery
- Excision
When might squamous cell carcinoma arise?
within background of sun-damaged skin
When can squamous cell carcinoma look like?
- Erythematous to skin coloured
- Papule
- Plaque-like
- Exophytic
- Hyperkeratotic
- Ulceration
What is the localisation of SCC?
Trunk and limbs > 2cm; Head / neck > 1cm; Periorificial zones
What are the margins of SCC like?
Ill-defined
How fast does SCC grow?
Rapidly growing
When is SCC common?
- Immunosuppressed patients
* Previous radiotherapy or site of chronic inflammation
What is the histology like in SCC?
- Grade of differentiation: poorly differentiated
- Acantholytic, adenosquamous, demosplastic subtypes
- Tumour thickness - Clark level: >6mm, Clark IV, V
- Invasion beyond subcutaneous fat
- Perineural, lymphatic or vascular invasion
What is keratocanthoma?
•Controversial entity
- Pseudo-malignancy vs variant of SCC
What are the characteristics of keratoacanthoma?
Rapidly enlarging papule that evolves into a sharply circumscribed, crateriform nodule with keratotic core
How does keratocanthoma resolve?
slowly over months to leave atrophic scar
Where do keratocanthoma occur?
- occur on head or neck / sun exposed areas
- Difficult to distinguish clinically and histologically from squamous cell carcinoma
What are investigations of SCC?
- Often clinical diagnosis sufficient
- Diagnostic biopsy may be taken if diagnostic uncertainty
- Ultrasound of regional lymph nodes ± FNA if concerns regarding regional lymph node metastasis
What is SCC treatment?
- Examination of rest of skin and regional lymph nodes
- Excision
- Radiotherapy
- Cemiplimab for metastatic SCC
When do you use radiotherapy SCC?
- Unresectable
- High risk features e.g. perineural invasion
What is the secondary prevention of SCC?
- Skin monitoring advice
- Sun protection advice
When does BCC arise?
within sun damaged skin
What are the main subtypes of BCC?
- Nodular
- Superficial
- Morpheic
- Infiltrative
- Basisquamous
- Micronodular
How common is nodular BCC?
- Most common subtype
- Accounts for approximately 50% of all Basal cell carcinomas
How does nodular BCC present?
shiny, pearly papule or nodule
What does superficial BCC look like?
Well-circumscribed, erythematous, macule / patch or thin papule /plaque
What does BCC morphoeic look like?
- Slightly elevated or depressed area of induration
- Usually light-pink to white in colour
- More aggressive behaviour
- Extensive local destruction
Is BCC mophoeic common?
less common
What is basisquamous BCC like?
Histological features of both basal cell carcinoma and squamous cell carcinoma
What is micronodular BCC like?
- Resembles nodular basal cell carcinoma clinically
2. More destructive behaviour – high rates of recurrence and subclinical spread
What are the investigations for BCC?
- Often clinical diagnosis sufficient
* Diagnostic biopsy may be taken
What are the differential diagnosis of BCC?
- Squamous cell carcinoma
- Adnexal (sebaceous) carcinoma
- Merkel cell carcinoma
What is the stages of treatment for BCC in Mohs?
- First thin layer removed
- Another thin layer removed
- Another thin layer removed
- Final layer of cancer removed
- examine each one before taking another so no margin taken
When is Mohs micrographic surgery used in BCC treatment?
- Recurrent basal cell carcinoma
- Aggressive subtype (morpheic / infiltrative / micronodular)
- Critical site (if nose/eye)
What are the other option of BCC treatment?
- Topical therapy e.g. 5-Fluorouracil, Imiquimod
- Photodynamic therapy
- Curettage (as iceberg can still reccur with this)
- Radiotherapy
- Vismodegib - selectively inhibits abnormal signalling in Hedgehog (Hh) pathway
What are some differential diagnsosi of SCC?
- BCC
- Viral wart
- Merkel cell carcinoma