Cutaneous Squamous Cell Carcinoma (SCC)

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Cutaneous squamous cell carcinoma\: second most common skin cancer in UK, incidence 77.3/100,000 in men,
34.1/100,000 in women.
Aetiology\: mutations in squamous keratinocytes in epidermis; mainly due to UVB exposure, p53 tumour suppressor gene
mutation.
Risk factors\: UV radiation, immunosuppression, fair skin (types I and II), solid organ transplant, increasing age, male sex,
chronic in
Symptoms\: skin changes (growing nodule, bleeding lesion), red
Features of SCC\:
Firm to palpate (may be nodular/plaque-like)
May ulcerate and bleed
May be tender/painful
May have a crusty (keratotic) top with a nodular base
Size is variable
Examination\: lesions typically in sun-exposed areas, may bleed, itch, crust; other sun damage signs include solar
lentigines, actinic keratosis.
Investigations\: dermatoscopy, biopsy (excisional, punch, incisional), ultrasound of lymph nodes, CT/MRI for staging or
metastasis.
Management\: 2-week wait referral; treatments include cryotherapy, surgical excision, Mohs micrographic surgery,
radiotherapy.
Complications\: surgical complications include bleeding, infection, pain, scarring, nerve damage, deformities.
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A comprehensive topic overview

Introduction

Cutaneous squamous cell carcinoma (SCC), a form of non-melanoma skin cancer (NMSC), is the second most common
type of skin cancer in the UK, following basal cell carcinoma.
1
Incidence rates are outdated and underreported, however, from 2013 to 2015 the incidence rate of primary SCC in England
was thought to be 77.3 per 100,000 person-years in men and 34.1 per 100,000 person-years in women.
2

Aetiology

In SCC, cancerous mutations occur in squamous keratinocytes in the epidermis, the outermost layer of the skin. 3
are three layers of the skin\: the epidermis, dermis and subcutaneous layer (hypodermis).
There
Within the epidermis, there are
and stratum basale. The squamous keratinocytes lie above the stratum basale in the stratum spinosum.
4Figure 1. Structure of the skin.
5
Figure 2. Layers of the epidermis.
6
Ultraviolet exposure (speci7
Chronic UV exposure will damage the DNA of the
squamous keratinocytes, leading to tumour formation. 8 9
Signature mutations include the p53 tumour suppressor gene.

Risk factors

Risk factors for SCC include\:
8
Ultraviolet radiation
Immunosuppression
Fitzpatrick skin types I and II (fairer skin)
Solid organ transplant recipients
Increasing age
Male sex
Ionising radiation
Sites of chronic in
8

Clinical features

History
Typical symptoms of an SCC may include\:
10
Skin changes (e.g. growing nodule, bleeding lesion, texture or colour change, ulceration, pain)
Red
Lymphadenopathy
Other important areas to cover in the history include\:
Ultraviolet risk\: sun exposure and use of sun protection
Systemic enquiry\: red
Past medical history\: skin cancer, immunosuppression, Bowen’s disease, actinic keratosis and solid organ transplant
recipients
Family history\: implies skin type, genetic tendency and sun exposure
Social history\: outdoors occupation, hobbies and tanning/use of sunbeds
Travel history\: chronic sun exposure
For more information, see the Geeky Medics guide to dermatological history taking.
Clinical examination
Characteristic features of SCC lesions include bleeding, itching and crusting and these lesions will typically appear in sun-
exposed areas (e.g. the lips, back of the hands and upper part of the face or scalp).
8,11
Other features of sun damage may be present near the lesion including\:
8,9
Age spots (solar lentigines)
Sunburn or sun tan
Excessive wrinkling caused by solar elastosis (age-related UV damage)
Actinic keratosis (pre-malignant lesions induced by UV damage)
Morphology SCC lesions
Typical features of a cutaneous squamous cell carcinoma include\:
11
Firm to palpate (may be nodular/plaque-like)
May ulcerate and bleed
May be tender/painful
May have a crusty (keratotic) top with a nodular base
Size is variable
For more information, see the Geeky Medics guide to examining a non-pigmented skin lesion.
Figure 3. A SCC on the cheek.
12
DermatoscopyA dermatoscope is a tool used to evaluate skin lesions by magnifying the lesion. 13
aid diagnosis and help distinguish between a SCC and a BCC.
14
In the context of SSCs it can be used to
Bowen's disease
Bowen’s disease (also known as SCC in situ) occurs when the cancerous cells are con15
progress into invasive SCC, so it is important to monitor and treat Bowen’s disease promptly.
It can also
Figure 4. Bowen’s disease lesion on the
cheek.
16
Actinic keratosis
Actinic keratosis involves the formation of precancerous scaly lesions on the skin. 17
risk of developing into an SCC, therefore monitoring and treatment are important.
18
Actinic keratoses have around a 10%
Figure 5. Multiple actinic keratoses
lesions on the scalp.
19
Both these conditions have similar risk factors to SCC (e.g. chronic UV exposure and Fitzpatrick skin types I and II).
Representative images of diverse skin types
Because of image reproduction rules, we are only able to directly include images with creative commons licencing.
Unfortunately, the majority of images of dermatological conditions available under this licence are of Caucasian
patients and fair skin tones.
We have included representative images here that we are not able to reproduce in this article directly, which we
encourage you to review\:
British Skin Foundation\: Squamous cell carcinoma
Primary care dermatology society
DermNet NZ\: Cutaneous squamous cell carcinoma in skin of colour

Di

Possible di
8
Actinic keratosis
Basal cell carcinoma
Seborrhoeic keratosisInvestigations
The 8
the lesion can be examined histologically.
20
This may comprise an excisional, punch or incisional biopsy so
Excisional or shave biopsy to remove the whole lesion is used if the lesion is small, in an accessible area, not present in a
cosmetically sensitive area and not near vital structures, so it can all be removed in one go.
20
Incisional/punch biopsy which samples only a small (usually 4mm) part of the lesion is used if the lesion is large, in an
inaccessible area, present in a cosmetically sensitive area or near vital structures, to con
planning of further treatment if required.
20
Other relevant investigations may include ultrasound of lymph nodes, CT and MRI for staging or if metastasis is
suspected.
8
Figure 6. Histology of Bowen’s disease\: Atypical keratinocytes are con
21
Figure 7. Histology of invasive SCC\: atypical keratinocytes involve all layers of the epidermis and invade the dermis.
22Diagnosis
Various classi
8
Histopathological
Clinicopathological
Border’s classi
Staging
The American Joint Commission on Cancer (AJCC) TNM system is commonly used to stage SCC. 23
categorised as either low risk or high risk, which helps to direct appropriate management.
High-risk features include\:
Size\: >2mm deep or >20mm wide
Site\: face, ear, genitals, hands, feet
Recurrence
Immunosuppressed individual
Poor di
Perineural invasion (histologically)
High tumour budding
They are broadly

Management

NICE suggests a 2-week wait (2WW) referral for potential SCCs to a skin cancer screening clinic.
24
Treatments range from cryotherapy, surgical excision, surgical curettage and cautery, Mohs micrographic surgery and
radiotherapy and will depend on various factors including the patient’s medical history (e.g. comorbidities), location of the
lesion and TNM staging.
8
Bowen's disease (SCC in situ)
For Bowen’s disease, destructive therapies such as cryotherapy or topical therapies like 5-
management.
8
Cryotherapy, a form of non-surgical destruction, commonly uses liquid nitrogen to freeze the skin lesion. 25
Topical 5-

8
Invasive SCC
For invasive SCC (i.e, SCC growing beyond the epidermis),
excision with a minimum of 4mm margins.
8
If the SCC is present in a cosmetically sensitive location like the face, then Mohs micrographic surgery, also known as
also margin-controlled excision, is the preferred treatment option.
8,25
Metastatic SCC
For metastatic SCC, 8
immunotherapy drugs are also now available for certain cases, for example, immune checkpoint inhibitors.
27
New
Prevention
Primary and secondary prevention includes the usage of broad-spectrum sun creams with UV-A and UV-B coverage,
physical sun protection, avoidance of the sun and discouraging the use of sunbeds.
8,28

Complications

Complications of surgical management of SCC may include\:
8,29
BleedingPost-operative infection
Pain
Scarring (including keloid)
Nerve damage
Physical deformities

References

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Reviewer

Dr Natalya Fox
Dermatology RegistrarRelated notes
Acne vulgaris
Basal Cell Carcinoma (BCC)
Cellulitis
Erythema Multiforme
Erythema Nodosum