Skin Flashcards
What are the three main types of skin cancer?
Basal-cell skin cancer (basal cell carcinoma)
Squamous cell skin cancer (SCC)
Malignant melanoma
What is the commonest form of skin cancer?
Basal cell carcinoma
What are the characteristics of basal cell carcinoma?
Slow-growing, locally invasive, malignant epidermal basal layer skin tumour
What are the risk factors for BCC?
Exposure to UV light is main aetiological factor
Fitzpatrick skin types I & II: light skin, tans poorly
Male
Mutations in PTCH, p53, ras
Albinism
Gorlin’s syndrome
Xeroderma pigmentosum
Increasing age
Previous skin cancers
Immunosuppression e.g. AIDs, transplantation
Carcinogens - ionising radiation, arsenic, hydrocarbons
What is Gorlin-Goltz syndrome?
Nevoid basal cell carcinoma syndrome
Rare autosomal dominant condition, mutation of PTCH1 gene
Early onset BCCS Broad nasal root Palmar and plantar pits Bifid ribs Hypertelorism - wide spaced eyes Calcification of faux cerebri
What are the clinical features of a typical nodular BCC?
TURP
Presence of irregular pink/skin coloured lesion
Commonly on face/neck
Telangiectasia
Ulceration
Rolled edges
Pearly edge
What are the clinical sub-types of BCC?
Nodular Superficial Morphoeic Pigmented Basosquamous
What are the features of nodular BCC?
Most cases of BCC Occur mostly on head Flesh/red coloured Well defined borders Overlying telangiectasias Rodent ulcer - central ulceration
What are the features of superficial BCC?
Erythematous plaque Mostly on trunk/limbs Slow-growing May be dry/crusted May have bluish tinge
Numerous of these may indicate arsenic exposure
What are the features of morphoeic infiltrative BCC?
Scar-like lesion or indentation Commonly occur on upper trunk or face Whitish, compact Poorly defined plaque/scar Deeply invasive
What are the features of pigmented BCC?
Difficult to distinguish from melanoma
Pigmentation due to melanin production, why it is hard
Often excised with 2mm margin as a result
What are the features of basosquamous BCC?
Rare but agressive
Increased risk of recurrence and metastasis
Differentiation towards SCC
Has macro and histopathological features of both
What surgical management is available for BCC?
Excision - wide local or Moh’s micrographic surgery for high risk lesions
Destructive - curettage, cautery, cryotherapy, carbon dioxide laser (these don’t provide histological sample, so low risk lesions only)
What non-surgical management is available for BCC?
Radiotherapy -
Adjuvant
Prevent recurrence e.g. incompletely excised margins
Recurrent BCC
High risk BCCs; and surgery not appropriate
NB risk of radiation induced BCC in those with Gorlin’s
Topical immunotherapy e.g. Imiquimod
PDT
What are the features of a high risk BCC lesion?
Size > 2cm
Site - around eyes, lips, ears
Poorly defined margins
Histological sub-type - morpoeic, infiltrative, micro nodular, basosquamous
Histological features - perineural, perivascular inv
Previous tx failure
Immunosuppression
What are the surgical excision margins for BCC?
Lesions should be excised down to subcutaneous fat to ensure entirety of skin; epidermis and dermis is included in sample
Low risk lesions - (small <2cm, well defined) margin of 4-5mm = 95% clearance
High-risk lesions - (large >2cm poorly defined) 5mm provides 83% clearance
Recurrent lesions - referral to Skin MDT, re-excision of scar 5-10mm margins or Moh’s surgery and radiotherapy
What is Moh’s surgery?
Surgical removal of tissue
Free margin removed can be less
Mapping piece of tissue, freezing and cutting, staining
Interpretation of slides, determines if any more needs to be removed
Possible reconstruction of surgical defect
What is the system used to describe a skin lesion?
A - asymmetry B - border irregularity C - colour (varies) D - diameter (greater than 6mm) E - evolving (change in shape, size or shade) F - funny looking
Describe how BCC grow
Slow growing
Locally Invading
Very rarely metastasis
What cells do BCC’s arise from?
Epidermal tumours arising from hair follicles
Describe the appearance of solar (actinic) keratoses:
On sun-exposed skin
Crumbly, yellow-white crusts
What is the risk associated with actinic keratoses?
Malignant change to squamous cell carcinoma may occur after several years
How should actinic keratoses be managed?
Cryotherapy or fluorouracil/imiquimod cream
Describe the appearance of Bowen’s disease:
Slow growing red/brown scaly plaque
How should Bowen’s disease be managed?
Cryo, topical fluorouracil, photodynamic therapy
Describe the appearance of keratoacanthoma:
Dome-shaped erythematous lesions that grow rapidly and often contain a central pit of keratin
name 3 genetic conditions associated with increased risk skin ca
- gorlins syndrome (PTCH1 gene mutation leading to increased risk nevoid BCC)
- xeroderma pigmentosa
- albinism
How should a suspected BCC be referred?
- routine referral if suspect BCC
- 2WW if concern that delay would have impact either bc or site or feature of the lesion
How should BCC be investigated?
- excision biopsy
- incision biopsy before non surgical treatment to confirm diagnosis
- examine for lymphadenopathy
- MRI or CT only when bony involvement suspected or tumour invaded major nerves, orbit or parotid gland
What is squamous cell carcinoma?
Malignant tumouR
Keratinising cells of the basal layer of the epidermis
Locally invasive
Potential to metastasise
What are the risk factors for SCC?
UV light
Fair skin
Chemical carcinogens - arsenic, chromium, soot, tar and pitch oils
HPV
Ionising radiation exposure
Immunodeficiency
Chronic inflammation - near chronic ulcers, lupus vulgaris
Genetic conditions e.g. albinism, xeroderma pigmentosum
Pre-malignant conditions e.g. Bowen’s disease
Where do most invasive SCCs originate from?
Actinic keratoses
What are the features of actinic keratosis?
Macule or patch
On areas that receive large amounts of sunlight: head and neck, dorsum of hands, forearms
Erythematous base
Overlying scale
Typically non tender
What is cutaneous squamous cell carcinoma in situ?
Bowen's disease Most common on lower limbs Erythematous, well defined borders, patches/plaques Round to oval shape Rough scale Grows very slowly
What are some differentials for Bowen’s disease?
Psoriasis
Invasive cSCC
Superficial BCC
Where can invasive cutaneous SCC occur?
Arise from any cutaneous surface
Most frequently head and neck
Legs, hands, forearms, shoulder, back, chest, abdomen
What are the characteristics of a well differentiated invasive cSCC?
Papule, plaque or nodule 0.5-1.5cm or larger Erythematous base Rough scale, crusting May have ulceration Firm, indurated on palpation
What are the features of a poorly differentiated invasive cSCC lesion?
Papule or nodule Granulomatous Lack scale May have ulceration, haemorrhage, necrosis Fleshy and soft on palpation
How do invasive cutaneous cSCC lesions evolve?
Grows over period of months
Becomes increasingly tender
More likely to ulcer and bleed
May present as a non-healing wound, asymptomatic
What are the differential diagnoses for invasive cSCC?
Actinic keratosis
Superficial BCC
Warts
Pyogenic granuloma
What are the investigations fo SCC?
Visual inspection and removal for histology where necessary
Excision biopsy - whole lesion excised
Incisional or punch biopsy if lesion in large, in cosmetically sensitive areas, close to vital structures
If advanced disease - imaging including CT scanning for bone or soft tissue spread, MRI scan
Clinically enlarged nodes should be examined histologically e.g. by fine needle aspiration
At which sites can squamous cell carcinoma of the skin develop from (predisposing sites)?
Actinic keratoses, lips of smokers, or in long standing ulcers (Marjolin’s)
How should Bowen’s disease be managed?
Cryo, topical fluorouracil, photodynamic therapy
Describe the appearance of keratoacanthoma:
Dome-shaped erythematous lesions that grow rapidly and often contain a central pit of keratin
What are the high risk features of cutaneous squamous cell carcinoma?
>2cm in size High risk locations - ear, lip, genitals Rapid growth Immunosuppressed patient Arisen from within trauma site Recurrent disease Incomplete excision
What management is available for SCC?
Complete surgical excision and all excised specimens sent for histological exam
Curettage and cautery to remove soft material from tumour, base of tumour then destroyed
Best in small lesions
Cryotherapy for small in situ SCCs and pre-cancerous lesions
Topical treatment with Imiquimod 5% for actinic keratosis
Photodynamic therapy - light therapy and a topical photosensitising agent
Radiotherapy
Moh’s micrographic surgery
What is a difference between BCC and SCC?
SCCs are less common than BCCs, but metastasise more frequently than BCCs
What are the features of suspicious of melanoma?
ABCDE
Asymmetry Border - irregular Colour - alterations Diameter >6mm Evolving lesions
What are risk factors for melanoma?
Exposure to UV light Severe sun burn Immunosuppression Skin types I and II Family history Genetic mutations
How does distribution between sexes differ in melanoma?
1.5x more common in men
In men lesions on trunk
In women, lesions on arms and legs
What is melanoma?
Originates from uncontrolled proliferation of melanocytes in the basal epidermis
Describe the typical tumour progression of melanoma?
Benign naevus - typical mole, controlled proliferation of melanocytes
Dysplastic naevus - atypical mole, abnormal proliferation results in pre-malignant lesion
Radical growth phase
Vertical growth phase - invade basement membrane, proliferate vertically downwards
Metastasis - malignant cells may spread to other areas
What are the clinical features of melanoma?
Mostly arise de novo
Appear as pigmented lesion with irregular border
Tendency to grow or change
ABCDE
What biopsy is available for melanoma?
Excision biopsy of the suspicious lesions
Completely excised with a margin of 1-2mm of healthy surrounding skin
Includes portion of subcutaneous fat to ensure full-thickness of dermis sampled
Orientation important - longitudinal lesions preferred on the limbs
Incisional biopsy - punch or incision for small sample for large lesions or close to vital structures - eyes, ears, nose
What are the major subtypes of melanoma?
Superficial spreading - initial radial growth progresses to vertical growth
Nodular - transition quickly to vertical growth
Acral lentiginous - under nails, hands and feet, black line on nail = Hutchinson’s sign
Lentigo maligna - common in elderly, chronically sun-exposed sites
Desmoplastic - very rare, due to abnormal deposits of collagen
What are the features of histological analysis of melanoma?
Clark level:
I-V histological classification for depth of invasion
Breslow thickness (mm): Measured from stratum granulosum of epidermis or from bottom of ulceration to the point of maximum infiltration
Ulceration:
Absence of intact epithelium overlying the lesion
Correlates with poorer prognosis, suggestive of aggressive tumour phenotype
Mitotic index
Indicator of cell turnover
Important histological finding
Number of mitoses per mm2
What are the investigations for melanoma?
Careful skin and lymph node examination
FNA and cytology if suspicious lymph node
Total body CT or PET-CT for high-risk lesions - those with aggressive lesions, or presence of known lymph node spread
LDH (lactate dehydrogenase blood marker of cell turnover) for risk stratifying
What is the staging of melanoma based on?
TNM system -
Tumour - breslow thickness (mm) +- presence of ulceration
Node - whether melanoma has spread to lymph nodes and how many
Mets
What is the AJCC (American Joint Committee on Cancer) system of staging?
Stage 0 - melanoma in situ
Abnormal cells only present in the top layer of skin - epidermis, not spread to dermis
Stage I
IA - <0.8mm thick, no ulceration
IB - <0.8mm, ulceration or 1-2mm thick, no ulceration
Stage II usually thicker but not spread
IIC is >4mm with ulceration
Stage III - lymph node involvement
Stage IV metastatic spread
What is the surgical management of melanoma?
Wide local excision for primary melanoma, removal of biopsy scar, margin depends on Breslow thickness
Senital lymph node biopsy under GA at same time as WLE - radio-labelled tracer and CT identifies hot spots, further shown in surgery with blue dye
Positive SLNB results in subsequent lymphadenectomy
Electro-chemotherapy
For locally advanced melanoma
Chemo agent given IV or injected into the tumour, then powerful pulses of electricity applied to the tumour
Increases permeability of tumour cell membranes so chemo agent can pass through
What is the medical management of melanoma?
Adjuvant therapy e.g. interferon alpha
Chemo, radio, immuno
Describe the clinical features of melanoma
- lesion changed in size
- irregularity of pigmentation (may need dermatoscope to appreciate)
- irregularity of outline
- size >6mm
- inflammation
- oozing or bleeding
- itch or altered sensation
- risk factors identified
- not all melanomas are pigmented but most are
what are the criteria for melanoma 2WW
- 2WW if 3 or more points from: 2 points: - change in size - irregular shape - irregular colour 1 point: - >6mm - inflammation - oozing - change in sensation
how should melanoma be investigated?
- narrow margin excisional biopsy initally
- dermoscopy
- sentinel node biopsy
- CXR, liver USS, CT CAP
- FBC, LFT, LDH
- bone scan
Describe the breslow scale
- about depth of invasion at biopsy, strongly correlated with survival
- Tis= top layer of skin
- T1= 1mm thick or less
- T2= melanoma between 1 and 2mm thick
- T3= 2-4mm thick
How can stage 0-2 melanoma be managed?
- PDT if insitu
- excision (see margins)
- imiquimod cream for stage 0 melanoma and surgery wants to be avoided
How should stage 3 (spread to nearest LN or blood vessel but no systemic spread) melanoma be managed?
- complete lymphadenectomy if node biopsy shows micromets
- lymph node dissection: palpable stage 3b-c or nodal disease detected by imaging
- adjuvant radiotherapy for stage 3b pr c unless reduction in risk of local reoccurrence outweighs side effect risk
- excision of tumour
How should stage 4 melanoma be managed?
- surgery to excise
- targeted treatments: dabrafenib for unresectable or metastatic BRAF V600+ve melanoma
- immunotherapy: ipilimumab (CTLA-4 blocker) for unresectable or metaststic melanoma in those who have had prior therapy
- cytotoxic chemo if immuno or targeted therapy not suitable
- palliative care
Describe the Glasgow 7-point checklist for malignant melanoma and when you should refer:
Major (2pts): change in size, shape, colour
Minor (1pt): inflammation, sensory change, diameter >6mm, crusting/bleeding
Refer if 3+
What is a lentigo maligna?
It is an area of “sun damaged skin” that is a melanoma in situ
Where do malignant melanomas metastasise?
Bone, brain, lung, liver
What are some poor prognostic indicators for malignant melanoma?
High Breslow thickness
Ulcerated
Node involvement
Location of head, neck, back of arms
