Skin Flashcards
(28 cards)
what is the pathophysiology of melanoma?
- acquired mutations = BRAF and NRAS which mutate due to UV affecting MAPK pathway leading to uncontrolled proliferation
-uncontrolled division of melanocytes which become invasive and metastasise
what are the phases of melanoma?
- melanomas have 2 growth phases, radical and vertical
- most superficial confined to epidermis with horizontal growth phase remaining in situ, slow growing
- further genetic changes may cause vertical growth in which malignant cells breach basement membrane invading deep tissue becoming invasive
- once reached dermis may spread via lymphatics or blood into lungs or brain
what are some risk factors for melanoma?
- UV exposure
- age
- previous skin cancer
- many moles 5<
- first degree relatives with melanoma
- Parkinson’s
- Fitzpatrick
- immunocompromised
what are the clinical key features of melanoma?
- unusual looking mole or freckle which may itch or bleed, in radial or vertical phase
- superficial melanomas consider ABCDE (more common)
- Asymmetry of shape and colour
- Border irregularity, smudgy or ill-defined margin
- Colour variation and change
- Diameter
- Evolving, enlarging
- Nodular consider EFG
- Elevated
- Firm to touch
- Growing
how might melanoma present in those with skin of colour?
- Thicker melanomas at diagnosis and highermortalityrates
- Significantly higher rates of melanomas in areas not exposed to the sun, including thesubungual,palmar,andplantarsurfaces (eg, acral lentiginous melanomain Pacific Islanders, blacks, and Asians)
- Non-cutaneousmelanomas (eg: mucosal melanoma, ocular melanoma)
what are some subtypes of melanoma?
superficial - most common
nodular
lentigo maligna melanoma
aural lentigous melanoma
what are some investigations of melanoma?
- dermoscopy
- Excisional biopsy of the lesion with a 2mm margin
- Sentinel lymph node biopsy if the Breslow thickness is >1mm
- PET or CT scans may be necessary in the presence of clinical suspicion for metastases- clinical with or without dermoscopy
how is melanoma managed?
- wide local excision
- lymphadenectomy
- targeted therapy like BRAF inhibition
- immunotherapy with MAB
- radiation - unfit for surgery, adjuvant or combo
- radiation for bony metastases, for symptom relief
- follow up!!
how might melanoma complicate?
- metastasis and systemic effects
- side effects from systemic or radiation therapy
- possible death
- surgical - infection, dehiscence, skin necrosis, incomplete resection
what is squamous cell carcinoma?
locally invasive, malignant, epidermal keratinocytes (protein that makes up skin, hair and nails) with potential to metastasise
what is the pathophysiology of SCC?
- combination of risk factors and UV radiation
- leads to signature gene mutation which affects cell signalling pathways
- causing increased epidermal growth factor release
- epidermal hyperplasia as a result leading to SCC
what are some risk factors for developing SCC?
- age
- heavy UV exposure
- smoking
- Fitzpatrick skin type 1,2
- chronic skin inflammation
- pre-malignant conditions like actinic keratosis
- previous skin cancer
- immunosuppression
how might you describe the features of an SCC?
- may be ulcerated, keratinocytes with crusted lesions
- They grow over weeks to months
- They are often tender or painful
- Located on sun-exposed sites, particularly the face, lips, ears, hands, forearms and lower legs
what are some conditions that predispose the occurence of SCC?
bowens disease - SCC in situ
actinic keratosis
marjolin ulcer
what are some high risk features of a SCC lesion?
size of lesion, metastases, health and fitness, proximity to major structures
how might you investigate SCC?
- clinical diagnosis
- incisional biopsy for histology
- excisional biopsy
- sentinel LN biopsy
- high risk - USS, XR, CT, MRI, LN biopsy
how might you manage an SCC?
may require flap or skin graft
- surgical excision with 3-10mm margin of normal tissue removal
- shave, curettage and electrocautery for small, thin and low risk
- Moh’s micrographic surgery
- radiotherapy
metastatic
- MDT with combo of surgery, radiotherapy, Cemiplimab, experimental targeted epidermal growth factor receptor inhibitors
what is Bowen disease?
common superficial form of keratinocyte cancer - aka intraepidermal SCC
- derived from squamous cells - flat epidermal cells that make keratin, the horny protein that makes up skin, hair and nails
- but ‘in situ’ meaning malignant cells confined to tissue of origin ie epidermis
how might Bowens disease present and what is the significance?
- irregular scaly plaques
- 5% may turn into invasive SCC
what is basal cell carcinoma?
Slow growing, locally invasive malignancy involving the basal skin layer
what is the pathophysiology of BCC?
exposure of UV radiation
leading to reduced cell mediated immunity, oxidative damage
PTCH - hedgehog signalling pathway damages
what are some risk factors of BCC?
- Fitzpatrick skin type 1,2 - “always burns, never tans”
- sun exposure
- P53 gene
- previous skin cancer
- family history
- age + UV exposure
- immunosuppression
what are some types of BCC?
nodular
superficial
mophoeic
basosquamous
how does BCC classically present?
nodular - ulcerated centre, shiny pearly edges, telangiectasia
superficial - scaly , irregular plaque, thin rolled translucent border, seen on younger, upper trunk and shoulders
