Skin Tumors and Cutaneous Oncology
Core concepts
Separate benign, premalignant, and malignant lesions and know the pathway for each. Basal cell carcinoma (BCC): pearly, telangiectatic, slow-growing, rarely metastasises. Squamous cell carcinoma (SCC): keratotic, ulcerated, risk of metastasis, preceded by actinic keratosis. Melanoma: ABCDE and the Breslow thickness as the key prognostic factor. Know the dermoscopic hallmarks (atypical network, blue-white veil, irregular dots/globules, regression).
Also learn: actinic keratosis and Bowen disease as SCC precursors; dermatofibroma and seborrheic keratosis as benign mimics; cutaneous lymphoma (mycosis fungoides with Pautrier microabscesses, Sézary syndrome) and Kaposi sarcoma (HHV-8).
Traps
- Confusing Breslow thickness (prognosis) with Clark level (invasion depth by layer).
- Assuming all pigmented lesions need excision - dermoscopy guides.
- Missing that SCC in immunosuppressed or transplant patients behaves aggressively.
- Nodular melanoma may lack pigment and present as a rapidly growing nodule.
Rule of thumb
For melanoma questions, the single most important prognostic variable is Breslow thickness; for management questions, margin depends on thickness. For non-melanoma skin cancer, ask whether the lesion is low- or high-risk by site, size, histology, and immunosuppression.