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 the epidermal basal keratinocytes. It has a high cure rate of 95%, with metastases being rare. Although it is a form of skin cancer, it is almost never life-threatening. It is the most common type of skin cancer in the UK and often forms a "rodent ulcer."

Pathology

• Basal Cell Carcinoma is the most common skin malignancy.
• It arises from the basal keratinocytes in the epidermis and adnexal structures.
• Gene defects on the sonic hedgehog signaling pathway are commonly observed.
• Lack of metastases may be due to "stromal dependency," where the tumor's existence depends on a specialized tumor stroma.

Aetiology

• Primarily related to ultraviolet (UV) radiation from the sun or from tanning beds.
• About half of cases show defects in the P53 tumor suppressor gene.
• More common in individuals with an inability to tan.
• Most common in individuals over 40 years of age.
• Not typically familial, except in cases of Gorlin's syndrome.

Risk Factors

• Excessive UV exposure from sun or tanning beds.
• Affects sun-exposed areas such as the face, neck, head, and ears.
• Outdoor activities, outdoor workers, or living in sunny climates increase risk.
• People with a fair complexion who burn easily and rarely tan.
• Radiation exposure, arsenic, immunosuppression, and xeroderma pigmentosum are additional risk factors.

Clinical Presentation

• Common sites include the face, head, neck, inner canthus, and behind the ear. It presents as a scab that bleeds and does not heal or as a new lump on the skin.
• Superficial BCCs can look like a red, scaly, flat mark on the skin.
• Other forms form a lump with a pearl-like rim surrounding a central crater, often with visible small red blood vessels across the surface.
• If untreated, BCCs can develop into an ulcer, leading to the name "rodent ulcer."
• BCCs are generally painless but can be itchy or bleed if caught.
• Advances via direct extension, destroying surrounding tissue. Very rarely does it spread to local lymph nodes.

Clinical Subtypes

• Nodular: Pearly edges, ulcerative, and cystic appearance.
• Pigmented: Resembling melanoma due to its dark pigmentation.
• Morpheic: Scar-like, pale plaques.
• Superficial: More localized and less invasive.

Investigations

• Skin Biopsy: Complete removal and biopsy are the most reliable methods for diagnosing BCC.

Management

• Surgery: Main treatment involves wide local excision under local anesthesia. Skin grafting may be required for larger excisions.
• Mohs Micrographic Surgery: Used for BCCs located near sensitive areas (e.g., nose, eyes, ears). It involves excising skin tissue and immediately examining it under a microscope to ensure the BCC has been entirely removed. If any BCC remains, additional tissue is removed. This process continues until all BCC is excised. This method is especially useful for recurrent or complex BCCs.
• Superficial BCC Treatment: Options include curettage and cautery (scraping and sealing the area with heat), cryotherapy (freezing with liquid nitrogen), and topical treatments with 5-fluorouracil (5-FU) or imiquimod.
• Photodynamic Therapy: A special cream is applied to the BCC, which is absorbed by the cells and destroyed by exposure to light at a specific wavelength. Available in some dermatology departments.
• Other Treatments: Local radiotherapy, cryotherapy, and intralesional interferon may be used in certain cases.
• Vismodegib: A recently approved chemotherapy for advanced or metastatic BCCs.

Prevention and Self-Check

• Skin Self-Exams: Check your skin for changes once a month. Ask a friend or family member to help check areas you cannot easily see, like your back.
• Sunscreen: Use a broad-spectrum sunscreen with SPF 30 or higher to protect against UVB, and choose one with the UVA circle logo or 4-5 UVA stars to protect against UVA. Apply generously 15–30 minutes before sun exposure and reapply every 2 hours or immediately after swimming or towel-drying.
• Limit Sun Exposure: Avoid sun exposure, especially between 10 a.m. and 4 p.m. Wear protective clothing, a wide-brimmed hat, and sunglasses.
• Keep Children Protected: Ensure babies and young children are kept out of direct sunlight.