Skin Cancer Flashcards Preview

Dermatology > Skin Cancer > Flashcards

Flashcards in Skin Cancer Deck (35)
Loading flashcards...
1
Q

What are the 2 main types of skin cancer?

A

Melanoma/non melanoma (BCC/SCC)

2
Q

What is a key factor in melanoma survival?

A

Tumour depth

3
Q

What are the Breslow Thickness’?

A

4mm=50%, Metastases = 5%

4
Q

What do you look for in melanoma diagnosis?

A

Asymmetry, Border, Colour, Diameter, Evolution

5
Q

What is a known sign of melanoma?

A

Ugly ducking sign

6
Q

What is the clinical presentation of BCC?

A

Slow growing lump or non healing ulcer. Painless. Translucent/pearly. Visible arborising blood vessels. Central ulceration (rodent), scaly plaque if superficial. If infiltrative morphoeic. Locally invasive, usually >40 yo but can be younger

7
Q

What is the clinical presentation of SCC?

A

Hyperkeratotic lump or ulcer, arises on sun damaged skin. Grows fast, can be painful &/or bleed. Majority-well differentiated low risk, minority opposite. Metastases : 5%, poor prognosis at this stage. Precursor lesions

8
Q

What are the precursor lesions of SCC?

A

Actinic keratoses and Bowen’s disease (carcinoma-in-situ)

9
Q

What is the self resolving skin lesion that can occur in SCC?

A

Keratoacanthoma

10
Q

What is required for a finding of Actinic Keratoses?

A

Multiple lesions- evidence for a field of abnormality

11
Q

What are high risk sites in SCC?

A

Ear, lip and scalp

12
Q

What are some risk factors for Skin cancer?

A

Sun exposure, genetic predisposition, immunosuppression, HPV infection, other environmental carcinogen - coal tar, smoking etc

13
Q

What are the 6 skin types?

A
Skin type I - always burns, never tans
Skin type II - usually burns, can tan
Skin type III - can burn, but usually tans
Skin type IV - always tans, never burns
Skin type V - ‘brown’ skin
Skin type VI - ‘black’ skin
14
Q

What sun exposure pattern is likely to be the cause of SCC?

A

Chronic, cumulative UV exposure

15
Q

What sun exposure pattern is likely to be the cause of BCC and Melanoma?

A

Intermittent, intense sunburn episodes

16
Q

What conditions can cause a genetic susceptibility to skin cancer?

A

DNA repair syndromes e.g. Xeroderma Pigmentosum, Albinism, Naevoid BCC (Gorlin’s) syndrome

17
Q

What environmental carcinogens are risk factors for skin cancer?

A

Ionising radiation, arsenic, coal tar, trauma, chronic ulceration etc

18
Q

What does Xeroderma Pigmentosum cause in relation to skin cancer?

A
photosensitivity  
 skin cancers on UV-exposed sites
 neurological degeneration
 Increased risk of other cancers
 Defect in one of seven Nucleotide 
Excision Repair (NER) genes (XPA - G)
19
Q

What is Naevoid BCC (Gorlin’s) Syndrome?

A

Autosomal dominant familial cancer syndrome

20
Q

What are the major features of Gorlin’s?

A
Major features
early onset/multiple BCCs
palmar pits
jaw cysts
ectopic calcification falx
21
Q

What are the minor features of Gorlin’s?

A
Minor features
skeletal abnormality
OFC >97th centile
cardiac/ovarian fibroma
medulloblastoma
22
Q

What level of risk are Hereditary Type VII collagen deficiency (RDEB) of developing skin cancer ?

A

High risk

23
Q

What are the hallmarks of cancer?

A
Autonomous growth signals
Insensitivity to anti-growth signals
Resist cell death (apoptosis)
Limitless potential to divide
Angiogenesis
Invasion and metastasis
24
Q

What are the emerging hallmarks and enabling characteristics of cancer?

A

Deregulating cellular energetics and avoiding immune destruction. Genome instability and mutation and tumour promoting inflammation

25
Q

What light causes sunburn and is stopped by window glass?

A

UVB

26
Q

What light is stopped by sunscreens, yet doesn’t usually cause sunburn?

A

UVA

27
Q

Describe the damage to DNA caused by UVA?

A

Indirect DNA damage, much more prevalent, penetrates more deeply into skin

28
Q

Describe the damage to DNA caused by UVB?

A

Direct DNA damage-1000x more damaging than UVA, only when sun is directly overhead

29
Q

What are some types of DNA damage?

A

Altered or missing base, incorrect base, UV signature mutation: pyrimidine dimer, insertion/deletion, strand break, crosslinking

30
Q

What occurs in the formation of UV signature mutations?

A

UV light induces covalent linkages producing cyclobutane pyrimidine dimers (CPDs) and 6,4 photoproducts. The photoproducts interfere with pairing during replication and lead to mutations. CPDs are most common, 3x more frequent than 6,4s, but 6,4s are more mutagenic.

31
Q

What happens when a mutator phenotype is formed?

A

Cells accumulate further mutations at a greatly increased rate because of failure of DNA repair

32
Q

What types of DNA repair exist?

A

Nucleotide excision repair, base excision repair, double strand break repair, mismatch repair

33
Q

What is the principle carcinogen in photocarcinogenesis?

A

UVB 290-320nm

34
Q

What happens in UV induced immunosuppression?

A

Dendritic cells lose ability to present antigen
T cells switch from ‘helper’ to ‘suppressor’; regulatory T cells predominate
Keratinocytes & DCs secrete immunosuppressive cytokines

35
Q

Describe the TP53 mutation in skin cancer

A

TP53 mutation – found in AK, carcinoma-in-situ & SCC
very early event; clonal patches of aberrant p53-cells in normal SE skin
relationship to carcinogenesis not clear
protects cells from apoptosis, allowing accumulation of other mutations