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OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Cutaneous squamous-cell carcinoma

Dermatology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull

Overview

Recognise invasive cutaneous squamous-cell carcinoma, identify clinical and pathological high-risk features, refer every suspected lesion urgently and coordinate excision, nodal assessment and prevention.

Record growth rate, pain, bleeding, ulceration, previous field treatment, scar or ulcer duration, immune state and prior cancers. Measure the lesion and palpate depth, fixation, named nerves and nodes. In darker skin, SCC has a greater proportional association with chronic scars and inflammation and may arise at non-sun-exposed sites; delayed recognition worsens stage.

Clinical recognition cannot reliably establish invasion depth. Urgent specialist biopsy should include adequate dermis and the most indurated area without compromising definitive surgery. Histology records differentiation, depth, level, perineural or lymphovascular invasion, subtype and margins. Pathological high-risk features determine wider excision, Mohs, imaging, nodal evaluation or adjuvant radiotherapy discussion.

Prevention continues after removal. Treat surrounding actinic field change, support sun protection and self-examination and coordinate transplant or haematology teams when immune suppression is modifiable. New neurological symptoms or a draining-basin node after treatment is an urgent recurrence signal, not a routine follow-up issue.

Key points

  • Suspect SCC in a persistent enlarging tender indurated keratotic, crusted or ulcerated lesion, particularly on chronically sun-exposed skin.
  • NICE recommends urgent suspected-cancer referral for every lesion clinically suspicious for cutaneous SCC.
  • High-risk features include lip or ear site, diameter over 2 cm, depth over 6 mm or beyond subcutaneous fat, poor differentiation, perineural invasion, recurrence and immune suppression.
  • Palpate the relevant nodal basin and document pain, numbness or weakness because clinical perineural and nodal disease alter urgency and staging.
  • Excision with histological margin assessment is standard; Mohs or wider specialist surgery is considered for high-risk, recurrent or tissue-critical tumours.
  • Do not curette, freeze or treat with field cream when invasive SCC is plausible; these approaches can delay depth and margin diagnosis.
  • A cutaneous horn is a reaction pattern, not a diagnosis; assess and sample the indurated base where SCC may be present.
  • Immune-suppressed patients need a lower biopsy threshold, rapid pathways and multidisciplinary review of prevention and immunosuppression.

Aetiology

01

Cumulative ultraviolet injury

Long-term ultraviolet exposure produces keratinocyte mutations and field cancerisation, especially on scalp, face, ears, lips and dorsal hands.

02

Immune suppression

Solid-organ transplantation, haematological malignancy and long-term immunosuppressive medicines greatly increase SCC incidence, multiplicity, recurrence and aggressive behaviour.

03

Chronic inflammation and scar

Burn scars, non-healing ulcers, draining sinuses, radiation sites and chronic inflammatory dermatoses can develop biologically aggressive SCC.

04

Oncogenic and chemical exposures

High-risk HPV at selected anogenital or periungual sites, arsenic and occupational carcinogens contribute to particular tumours.

Pathophysiology

  1. 1
    Keratinocyte dysplasia

    Accumulating mutations progress from actinic keratosis or in-situ disease to atypical keratinocytes invading through basement membrane.

  2. 2
    Destructive dermal invasion

    Tumour nests produce keratin and infiltrate dermis, creating an indurated scaly, crusted, ulcerated or horn-forming lesion.

  3. 3
    Perineural spread

    Cancer tracks along nerves and causes disproportionate pain, paraesthesia, numbness or motor deficit with increased recurrence risk.

  4. 4
    Lymphatic metastasis

    High-risk tumours spread to regional nodes, with risk shaped by site, diameter, depth, differentiation, nerve invasion and immune state.

Clinical features and red flags

Indurated keratotic lesion

A firm tender papule, plaque or nodule has adherent scale, keratin, crust or a central ulcer and progressively enlarges.

Cutaneous horn base

A conical keratin projection with a thick, painful or indurated base raises concern for invasive SCC beneath it.

Lip or ear tumourRed flag

Persistent keratotic ulceration on vermilion lip or pinna carries higher metastatic risk and demands urgent referral.

Perineural symptomsRed flag

Pain, tingling, numbness, facial weakness or other motor loss near a lesion suggests nerve invasion.

Nodal diseaseRed flag

A new firm regional node, parotid mass or in-transit nodule may represent metastasis and requires urgent imaging and sampling.

Red flags requiring action

  • Rapid growth, severe pain, numbness, fixation, recurrent tumour, lip or ear site, diameter over 2 cm, immune suppression, palpable nodes or chronic-scar ulceration requires urgent suspected-cancer referral and high-risk staging.

Investigations

  1. 01
    Deep representative biopsyFirst step
    Why
    Confirm SCC and measure invasive and pathological risk features.
    Interpretation and limitations
    Include sufficient dermis from the indurated component; a superficial shave may show dysplasia but miss invasion.
  2. 02
    Histopathological risk report
    Why
    Record diameter, depth, differentiation, invasion plane, nerves, vessels and margins.
    Interpretation and limitations
    High-risk features are combined rather than judged from one item and should trigger multidisciplinary management.
  3. 03
    Regional-node examination and ultrasound
    Why
    Detect nodal spread in high-risk or clinically suspicious disease.
    Interpretation and limitations
    Ultrasound-guided cytology or core biopsy confirms suspicious nodes; normal palpation does not exclude microscopic disease.
  4. 04
    MRI or CT
    Why
    Assess clinical perineural, bone, deep soft-tissue or nodal extension.
    Interpretation and limitations
    Choose imaging by anatomy and multidisciplinary advice; MRI is particularly useful for named-nerve spread.
  5. 05
    Immune and field-risk review
    Why
    Identify transplant, haematological, medicine and chronic-wound factors that change surveillance.

Differential diagnosis

01

Keratoacanthoma

A rapidly growing symmetrical crateriform nodule may regress, but cannot be reliably separated from SCC and is managed as malignant until histology.

02

Actinic keratosis and Bowen disease

Rough macules and well-demarcated in-situ plaques lack proven dermal invasion but may harbour or progress to invasive SCC.

03

Basal-cell carcinoma

A pearly rolled border with arborising vessels suggests BCC, while keratin, tenderness and faster growth favour SCC.

04

Inflamed seborrhoeic keratosis

A stuck-on lesion can crust and itch, but persistent induration, ulceration or growth requires biopsy rather than reassurance.

Management

01Suspected SCCRefer every invasive suspicion urgentlyFirst stepA persistent indurated keratotic, ulcerated or rapidly growing lesion could represent invasive SCC.+
  1. 1Measure and document morphology, growth, site, immune status, neurological symptoms and regional nodes.
  2. 2DefinitiveMake an urgent suspected-cancer referral, leaving the lesion available for appropriately deep biopsy and definitive planning.
  3. 3Safety-net accelerated growth, bleeding, pain, numbness or nodes and track attendance and pathology outcome.
02Confirmed high-risk SCCStage and control marginsHistology or clinical context shows high-risk site, size, depth, subtype, nerve involvement, recurrence or immune suppression.+
  1. 1Discuss in the specialist multidisciplinary team and image nerves, bone or nodes where indicated.
  2. 2

Complications

01

Local tissue destruction

Invasion of cartilage, bone, lip, ear, eyelid or digit can impair function and require major reconstructive surgery.

02

Regional nodal metastasis

Firm nodes in parotid, cervical, axillary, epitrochlear or inguinal basins may represent spread and change stage and treatment.

03

Perineural disease

Clinical or microscopic nerve invasion increases local recurrence and can extend toward skull base with pain or cranial neuropathy.

04

Multiple future tumours

Field cancerisation and ongoing immune or ultraviolet risk lead to additional SCC, BCC and actinic keratoses.

Monitoring and follow-up

  • Confirm that pathology documents depth, differentiation, perineural or lymphovascular invasion and margin status.
  • At follow-up examine scar, in-transit pathway and nodal basin and ask about pain, numbness and weakness.
  • Perform whole-skin surveillance proportional to immune status, tumour burden and field cancerisation.
  • Teach rapid self-referral for a new growing keratotic lesion, non-healing ulcer, scar nodule or lymph node.
  • Coordinate transplant, haematology or rheumatology teams before any immunosuppression change.

Special situations

Tenderness is informative

Pain in a keratotic lesion raises invasive and perineural concern rather than proving simple inflammation.

The horn hides histology

Risk resides in the lesion beneath a keratin horn, so the base needs diagnostic assessment.

Depth beats surface

A modest-looking lesion invading beyond subcutaneous fat can be higher risk than a broad in-situ plaque.

Nodes follow anatomy

Scalp and facial tumours may drain to parotid or cervical nodes, while limbs use axillary, epitrochlear or inguinal basins.

Common pitfalls

  1. 01

    Using a routine referral because the lesion resembles a keratoacanthoma despite inability to exclude SCC.

  2. 02

    Taking a superficial sample that cannot assess invasion depth.

  3. 03

    Failing to palpate regional nodes or ask about sensory change.

  4. 04

    Treating a cutaneous horn with cryotherapy without diagnosing its base.

  5. 05

    Assuming SCC in darker skin must be on sun-exposed skin and missing a chronic-scar lesion.

Practice

Two practice questions

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Question 1 of 2
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DermatologyOriginal SBA

Tender keratotic ear nodule

An enlarging tender keratotic nodule on the pinna has ulcerated over six weeks. What is the correct referral action?

Choose one answer, then submit
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Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG12 suspected cutaneous SCC referralUrgent referral requirement.
  • British Association of Dermatologists squamous-cell carcinomaRecognition, high-risk features, treatment and follow-up.
  • BAD cutaneous SCC guideline 2020Risk stratification, surgery, staging and surveillance.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
Interpretation and limitations
Do not independently reduce essential immunosuppression; coordinate risk modification with the treating specialty.
Use margin-controlled or specialist excision and assess need for nodal treatment or adjuvant radiotherapy.
  • 3Coordinate immune-risk modification and establish more intensive scar, node and whole-skin surveillance.
    • 03Possible recurrence or metastasisEscalate scar, nerve and node changeEscalationA treated patient develops scar induration, ulceration, neurological symptoms or a draining-basin mass.+
    1. 1Arrange urgent examination of scar, nerves, in-transit skin and nodes and retrieve prior pathology and margins.
    2. 2Biopsy the suspicious lesion or node and obtain anatomy-directed imaging.
    3. 3Return confirmed disease to the skin-cancer multidisciplinary team for surgery, radiotherapy, systemic treatment and supportive care.