Basal cell carcinoma

Malignant skin tumor of basal epidermal (keratinocyte) origin; slow-growing, locally invasive, and rarely metastasizes.

• Most common skin cancer worldwide; usually not life-threatening but can cause local destruction if untreated. Frequently appears on exams contrasting its pearly appearance and minimal metastatic risk with squamous cell carcinoma and melanoma.

• Older fair-skinned adults with a pearly, waxy papule or nodule on sun-exposed areas (e.g., nose, face). Lesion often has visible telangiectasias, a rolled border, and may ulcerate or bleed chronically ("rodent ulcer" if advanced).
• Multiple clinical types: nodular BCC (classic pearly nodule with telangiectasia), superficial BCC (flat reddish scaly patch, often on trunk), pigmented BCC (contains dark pigment, mimicking melanoma), and morpheaform BCC (scar-like, infiltrative).

1. Any persistent or non-healing skin lesion should be biopsied to confirm diagnosis (excisional biopsy for small lesions, punch/incisional for larger). Pathology of BCC shows nests of basaloid cells with peripheral palisading nuclei.
2. After treating a BCC, schedule regular skin exams for new lesions — patients with one skin cancer are at higher risk of additional BCCs or other skin cancers.

1. First-line treatment is surgical excision with clear margins. For high-risk or cosmetically sensitive areas (face), use Mohs micrographic surgery to ensure complete removal while sparing tissue.
2. Small, low-risk lesions can be treated with curettage and electrodessication or cryotherapy. Superficial BCCs may be managed with topical 5-FU or imiquimod creams, or photodynamic therapy.
3. Advanced or unresectable BCC (very rare metastasis) can be treated with radiation therapy or hedgehog pathway inhibitors like vismodegib.

• Think "pearly papule" = BCC (a shiny, translucent lesion with telangiectatic vessels is classic for basal cell carcinoma).
• "Rodent ulcer" is an old term for BCC that ulcerates and gnaws into tissue like a rodent.
• Histology buzzword: palisading nuclei (tumor cells at the periphery of nests line up in a palisade) is characteristic of BCC.

• Pathology showing perineural invasion or patient reports numbness/tingling → indicates aggressive tumor spread along nerves; requires Mohs surgery (and often adjuvant radiation).
• Morpheaform/infiltrative subtype or recurrent BCC → higher risk of deep tissue invasion and recurrence; manage with Mohs and close follow-up.

1. Suspicious skin lesion (non-healing, pearly, or bleeding) → perform skin biopsy for diagnosis.
2. If biopsy confirms BCC, assess risk factors: location (e.g., face or ear = high risk), size, histologic subtype (nodular vs morpheaform), margins, and perineural involvement.
3. Choose treatment based on risk: excision for most localized BCCs; Mohs surgery for high-risk or facial lesions; consider topical or less invasive therapies for superficial BCC when appropriate.
4. Follow up with regular dermatologic exams (at least annually) to monitor for recurrence or new skin cancers (patients with BCC have an increased risk of SCC, melanoma, and additional BCCs).

• Elderly fair-skinned man with a slowly growing pearly papule on the nose that bleeds occasionally and has telangiectasia and a rolled border → Basal cell carcinoma.
• Patient with a pigmented but shiny, smooth-bordered skin nodule with a few telangiectasias (mimicking a mole) → Pigmented BCC (distinguished from melanoma by its pearly translucent areas and lack of irregular borders).