Makindo Medical Notes

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 tumor originating from epidermal basal keratinocytes. It has a high cure rate (~95%) and very rarely metastasises. It is the most common type of skin cancer in the UK and often forms a classic “rodent ulcer.” 🐭

🧬 Pathology

• BCC is the most common skin malignancy.
• Originates from basal keratinocytes in the epidermis/adnexal structures.
• Gene defects in the sonic hedgehog signalling pathway are often present.
• Lack of metastases is thought to reflect stromal dependency (requires tumour stroma to survive).

☀️ Aetiology

• Main cause: ultraviolet (UV) radiation (sunlight or tanning beds).
• ~50% have defects in the P53 tumour suppressor gene.
• More common in those unable to tan (fair-skinned).
• Predominantly affects those >40 years old.
• Familial cases rare, except in Gorlin’s syndrome.

⚠️ Risk Factors

• Excessive UV exposure (sun/tanning beds).
• Sun-exposed sites: face, neck, scalp, ears.
• Outdoor workers, outdoor activities, sunny climates.
• Fair skin, burns easily, rarely tans.
• Other risks: radiation, arsenic, immunosuppression, xeroderma pigmentosum.

👁️ Clinical Presentation

• Sites: face, head, neck, inner canthus, behind ear.
• Appears as a non-healing scab or new skin lump.
• Superficial BCC: red, scaly, flat patch.
• Nodular: pearly rim, central ulcer, telangiectasia.
• If untreated → classic “rodent ulcer” with tissue destruction.
• Usually painless, may itch or bleed.
• Locally invasive; rarely spreads to nodes.

🔎 Clinical Subtypes

• Nodular: Pearly edges, ulcerative, cystic.
• Pigmented: Dark, mimics melanoma.
• Morpheic: Scar-like, pale plaques.
• Superficial: Flat, erythematous, less invasive.

🧪 Investigations

• Skin Biopsy: Excision biopsy is diagnostic and often therapeutic.

💉 Management

• Wide Local Excision: Main treatment (may require grafting if large).
• Mohs Micrographic Surgery: Best for sensitive/recurrent sites (nose, eyes, ears). Tissue is removed layer by layer until clear.
• Superficial BCCs: Curettage & cautery, cryotherapy, or topical 5-FU / imiquimod.
• Photodynamic Therapy: Light-activated cream; used in some dermatology units.
• Other: Radiotherapy, cryotherapy, intralesional interferon.
• Vismodegib: Oral therapy for advanced/metastatic BCC (hedgehog pathway inhibitor).

🛡️ Prevention & Self-Check

• Skin self-exams: Check monthly; ask partner/family to check back/hidden areas.
• Sunscreen: Use SPF ≥30, broad-spectrum (UVA + UVB). Reapply every 2h, after swimming or towel-drying.
• Sun avoidance: Stay in shade 10am–4pm. Use hats, sunglasses, clothing.
• Children: Never expose babies/young children to direct sunlight.