Related Subjects:
|Nikolsky's sign
|Koebner phenomenon
|Erythema Multiforme
|Pyoderma gangrenosum
|Erythema Nodosum
|Dermatitis Herpetiformis
|Lichen Planus
|Acanthosis Nigricans
|Acne Rosacea
|Acne Vulgaris
|Alopecia
|Vitiligo
|Urticaria
|Basal Cell Carcinoma
|Malignant Melanoma
|Squamous Cell Carcinoma
|Mycosis Fungoides (Sezary Syndrome)
|Xeroderma pigmentosum
|Bullous Pemphigoid
|Pemphigus Vulgaris
|Seborrheic Dermatitis
|Pityriasis/Tinea versicolor infections
|Pityriasis rosea
|Scabies
|Dermatomyositis
|Toxic Epidermal Necrolysis
|Stevens-Johnson Syndrome
|Atopic Eczema/Atopic Dermatitis
|Psoriasis
🧴 Basal Cell Carcinoma (BCC) is a slow-growing malignancy of epidermal basal keratinocytes.
It rarely metastasises, has a high cure rate (~95%), and is the most common skin cancer in the UK.
Classic presentation: “rodent ulcer” 🐭. Early recognition is essential to prevent local tissue destruction.
🧬 Pathophysiology
- Originates from basal keratinocytes in the epidermis and hair follicle bulge stem cells.
- UV radiation → DNA damage (pyrimidine dimers) → mutations in key genes (TP53, PTCH1, SMO) → uncontrolled proliferation.
- Sonic Hedgehog (SHH) pathway: PTCH1 receptor loss-of-function → constitutive SMO activation → basal cell proliferation.
- Lack of metastasis may relate to stromal dependency; BCCs require surrounding dermal stroma for survival and growth.
- Chronic inflammation and immunosuppression can promote tumour growth.
☀️ Aetiology & Risk Factors
- UV exposure: cumulative sun exposure, intermittent intense burns, tanning beds.
- Fair skin, blue/green eyes, inability to tan, freckling.
- Age >40; incidence increases with age.
- Genetic predisposition: Gorlin’s syndrome (nevoid basal cell carcinoma syndrome), XP (xeroderma pigmentosum).
- Other: ionising radiation, arsenic exposure, immunosuppression, chronic ulcers/scars.
👁️ Clinical Features
- Sites: face (nose, eyelids, inner canthus), neck, scalp, ears.
- Superficial BCC: red, scaly, slightly raised patch.
- Nodular BCC: pearly rim, central ulceration, telangiectasia.
- Pigmented BCC: brown-black, may mimic melanoma.
- Morpheic/sclerosing BCC: pale, scar-like plaque, more infiltrative.
- Symptoms: usually painless, may bleed, itch, or crust. Slow local growth; rarely invades deeper structures or metastasises.
🔎 Investigations
- Skin Biopsy: Excisional or punch biopsy confirms diagnosis; often therapeutic for small lesions.
- Imaging (CT/MRI) for large, recurrent, or aggressive tumours invading bone or orbit.
💉 Management
- Wide Local Excision: Standard therapy; margins depend on subtype and size.
- Mohs Micrographic Surgery: Layer-by-layer excision with histological control; preferred for cosmetically sensitive or recurrent lesions.
- Superficial BCC: Curettage & cautery, cryotherapy, topical 5-FU or imiquimod, photodynamic therapy.
- Advanced/Metastatic BCC: Vismodegib or sonidegib (hedgehog pathway inhibitors).
- Radiotherapy: Alternative for poor surgical candidates.
🛡️ Prevention & Self-Check
- Monthly skin self-examination; partner/family checks hidden areas.
- Broad-spectrum sunscreen SPF ≥30, reapply every 2 hours and after swimming/towel-drying.
- Sun avoidance: 10am–4pm, shade, protective clothing, hats, sunglasses.
- Children: avoid direct sunlight; educate on lifelong UV protection.
📚 UK Guidance References
