15: Skin Cancer (27.02.2020) Flashcards

Question

What does Host Response to UV light depend on?

Answer 1

Determined by genetic influences especially skin phototype -> Fitzpatrick phototypes

Answer 2

1 - Always burns never tans II - Usually burns, sometimes tans III - Sometimes burns, usually tans IV - Never burns, always tans V - Moderate constitutive pigmentation - Asian VI - Marked constitutive pigmentation - Afrocaribean - 1+2 are most susceptible to skin cancer - 3-6 tend not to get skin cancer.

Answer 3

- Melanin pigmentation is responsible for skin colour - Produced by melanocytes within the basal layer of the epidermis - Skin colour depends on the amount and type of melanin produced not the density of melanocytes (which is fairly constant) - > in people with darker skin, melanocytes make more melanin

Answer 4

- sit on the basement membrane in the epidermis - dendritic appearance - comunicate with keratinocytes - after UV exposure keratinocytes have paracrine effects: secrete MSH which will affect the adjacent melanocyte and make it produce more malenin - melanin will go down dendritic processes and go to the keratinocyte - keratinocytes take up the melanin and places it around the nucleus, protecting it from UC exposure - this is what happens in tanning. Generally 1 melanocute for every 5 keratinocytes, dependant on the skin type.

Answer 5

- Eumelanin – brown or black - Phaeomelanin – yellowish or reddish brown - Melanin is formed from tryosine via a series of enzymes - in skin types 2 and 3 there is a ratio between the 2 melanin types. - MCR1 gene >20 gene polymorphisms Variation in eumelanin : phaeomelanin produced Explains different hair colour and skin types Melanin dictates skin sensitivity to UV damage

Answer 6

>20 gene polymorphisms Variation in eumelanin : phaeomelanin produced Explains different hair colour and skin types

Answer 7

- most dangerous kin cancer - Malignant tumour of melanocytes - Melanocytes become abnormal - Atypical cells and architecture Caused - by UV exposure - Genetic factors Risk of metastasis

Answer 8

- (melanoma in situ) - one of the hallmarks of melanoma: - Proliferation of malignant melanocytes within the epidermis (confined to the epidermis) - No risk of metastasis - quite common in elderly patients - flat, dark irregular patches. - Irregular shape Light & dark brown colours Size usually >2.0 cm - treatment can be excision

Answer 9

Lentigo maligna melanoma is invasive, lentigo maligna is not. - lentigo maligna melanoma is derived from lentigo maligna, SSMM is not.

Answer 10

- Lateral proliferation of malignant melanocytes - Invade basement membrane - Risk of metastasis

Answer 11

ABCD rule - Asymmetry - Border irregular - Colour variation (dark brown-black) - Diameter >0.7mm and increasing - Erythema

Answer 12

- If a lesion seems to have lost pigmentation -> regression -> immune system has fought it off - You think this is a good sign, however, the lesion may have spread already.

Answer 13

- Regression describes an area where it appears there had been melanoma cells, but these have been destroyed by the immune system and replaced with inflammation or scar tissue. - you would think that it is a good sign, however, the cancer may have already spread? find out more here

Answer 14

- Vertical proliferation of malignant melanocytes (no previous horizontal growth) - Risk of metastasis

Answer 15

- Downward proliferation of malignant melanocytes FOLLOWING PREVOIUS HORIZONTAL GROWTH (vs. nodular melanoma) - Nodule developing within irregular plaque - Prognosis will become WORSE

Answer 16

- specific type of melanoma that appears on the palms of the hands, the soles of the feet, or under the nails. - these are most common skin cancer in dark skin types

Answer 17

- the malignant cells have little or no pigment (truly amelanotic (no pigment at all) is quite rare) - many hypopigmented lesions are labelled as amelanotic

Answer 18

``` Superficial spreading Nodular Lentigo maligna melanoma Acral lentiginous Amelanotic ```

Answer 19

Breslow thickness -> measurement from granular layer to the bottom of the tumour.

Answer 20

- UV irridation - sunburns during childhood - skin types 1 and 2 - more the burin got skin then sunlight exposure in general (intermittent burning exposure in unacclimatised fair skin) - personal history of melanoma - FH of dysplastic nevi or melanoma - atypical/dysplastic nevus synrome

Answer 21

- skin lesion that erupts in sun-damaged skin, rather like a little volcano. - grows for a few months; then it may shrink and resolve by itself - considered to be a variant of the keratinocyte or non-melanoma skin cancer, (SCC). - As it cannot be clinically reliably distinguished from more severe forms of skin cancer, keratoacanthomas are usually treated surgically. - generally excisable

Answer 22

- Malignant tumour of keratinocytes (e.g. horn. growing out of the lump) - Caused by UV exposure HPV Immunosuppression May occur in scars or scarring processes - may appear on the lips, ears, legs (in women mainly because of sun exposure) - Risk of metastasis (but much much less than melanoma, for a poorly differentiated one perhaps 10%) - makes keratin if well differentiated

Answer 23

- e.g. horn of keratin growing out of the lump

Answer 24

= basal cell carcinoma - Malignant tumour arising from basal layer of epidermis - Caused by sun exposure Genetics - Slow growing - Invades tissue, but does NOT metastasise - Common on face but can occur elsewhere. - can be flat (superficial BSS), some have edge? - can appear on eyelid, lost eyelashes on that spot (loss of eyelashes is usually a tumour) - blood vessles with small branches like a tree (arborising)

Answer 25

arborising (branching like trees) small blood vessles

Answer 26

- Mycosis fungoides | - Kaposi's sarcoma

Answer 27

- type of cutaneous or skin lymphoma - slowly progressing disease (can take decades to progress) - A sign of mycosis fungoides is a red rash on the skin. - can be controlled through various waays

Answer 28

- associated with HIV and HHV8 infections - purplish - orientation of the plaque often goes along ht lines of the skin - sometimes on palate - treatment by - treating the HIV - chemo/radiotherapy

Answer 29

- Rare autosomal recessive condition | - predisposition to HPV induced warts and SCCs

Answer 30

- Incidence of Melanoma and NMSC increasing in Western Countries - Mainly pale skin people effected - UV exposure a significant risk factor - UVB most important for carcinogenesis – mutations in key genes - Other factors involved in skin cancer development - HPV infection - immunosuppression - age - genetics eg MCR1 polymorphisms - Treatment is still mainly surgical

Answer 31

(dermis) - stratum basale - stratum spinous - stratum granulosum - stratum lucidum - stratum cornea (dead keratinocytes, those on the surface flake off)

Answer 32

- Gorlin syndrome, also known as nevoid basal cell carcinoma syndrome, is a condition that affects many areas of the body and increases the risk of developing various cancerous and noncancerous tumors. - the type of cancer diagnosed most often is BCC, which is the most common form of skin cancer. - Individuals with Gorlin syndrome typically begin to develop basal cell carcinomas during adolescence or early adulthood. - These cancers occur most often on the face, chest, and back. - The number of basal cell carcinomas that develop during a person's lifetime varies among affected individuals. - Some people with Gorlin syndrome never develop any basal cell carcinomas, while others may develop thousands of these cancers.

Answer 33

- tumour suppressor gene - regulates the cell cycle - important in suppressing cancer in multicellular organisms

Answer 34

- the numbers fo melanocytes don't really differ | - what differs is how much melanin they produce.

Answer 35

Tyrosine -> DOPA -> Dopaquinone -> Eumelanin or Pheomelanin -> Melanin

Answer 36

- superficial BCC | - nodular BCC

Brainscape's Knowledge GenomeTM

15: Skin Cancer (27.02.2020) Flashcards

Brainscape's Knowledge Genome^TM