Accurate diagnosis of dermatological malignancies depends on detailed lesion descriptions and knowledge of typical anatomical sites of occurrence. Sun exposure represents the most potent risk factor for all types of skin cancer, making patient education regarding sun avoidance essential. Additionally, a history of five or more blistering sunburns prior to age 20 increases the risk of malignant melanoma by 80%.
Clinical Concept: Consistent use of high sun protection factor (SPF) sunscreen is critical and helps reduce—but does not eliminate—the risk of basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). However, sunscreen use likely does little to minimize malignant melanoma risk directly.
Comprehensive skin examination enables the detection of both premalignant lesions (e.g., actinic keratoses, keratoacanthoma) and overt cutaneous malignancies.
Malignant melanoma arises from pigment-producing melanocytes and represents the most common fatal dermatological malignancy. The “ABCDE” mnemonic assists in clinical evaluation:
Basal cell carcinoma (BCC) features a long latency period and low metastatic risk, though untreated lesions can cause significant local tissue destruction, deformity, or loss of function. The mnemonic “PUT ON” helps identify key features:
Squamous cell carcinoma (SCC) grows more rapidly than BCC and possesses a low but clinically significant metastatic risk. SCC can arise spontaneously or from precursor lesions like actinic keratoses or keratoacanthomas. The mnemonic “NO SUN” outlines its characteristics:
Actinic keratoses (AK) are UV-induced precancerous skin lesions that can evolve into SCC at an estimated rate of 1 in 100. They begin as small, rough, sandpaper-like patches (3–10 mm in diameter) that are often easier to identify by light palpation than by visual inspection alone. Over time, AK lesions typically enlarge, become scaly and red, and frequently recur with crusting after patients attempt to scratch or pick them off.
While clinical mnemonics guide initial identification, definitive diagnosis of cutaneous malignancy requires a skin biopsy. Definitive intervention depends directly on histological confirmation and staging.
| Condition / Category | Modality / Agent | Regimen & Clinical Details |
|---|---|---|
| Actinic Keratoses (Destructive/Topical) | Cryotherapy (Liquid Nitrogen) | Destroys lesions with crusting for ~2 weeks, resulting in excellent cosmetic outcomes. |
| Actinic Keratoses (Topical Chemotherapy) | 5% Fluorouracil (5-FU) cream | Daily Regimen: Applied 1–5% once daily for 2 to 3 weeks until crusted. Pulse Regimen: Applied 5% once daily 1–2 days/week for 7 to 10 weeks (provides similar efficacy without significant crusting/discomfort). |
| Actinic Keratoses (Alternative Topicals) | 5% Imiquimod cream, Topical Diclofenac gel, PDT | Photodynamic therapy (PDT) utilizes topical delta-aminolevulinic acid. |
| Actinic Keratoses (Rapid Topicals) | Ingenol mebutate gel (Picato®) | Provides faster treatment: 2-day dosing (0.05% gel for trunk/extremities) or 3-day dosing (0.015% gel for face/scalp). |
| Actinic Keratoses (Resurfacing) | Chemical Peels & Laser | Additional destructive option for broad field treatment. |
| Surgical Management (BCC/SCC) | Excision & Mohs Micrographic Surgery | Primary treatment involves surgical removal with clean margins. Mohs surgery is recommended for tumors with aggressive histological patterns or invasive features. |
| Malignant Melanoma | Surgical Excision & Staging | Driven by lesion thickness/depth, staging, and sentinel lymph node biopsy findings. Expert dermatology consultation is strongly advised. |
Clinical Concept: Nonsurgical options for localized BCC and SCC include lesion destruction via cryotherapy, electrodesiccation with curettage, focal radiation, and topical cancer chemotherapy.
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2. de Oliveira ECV, da Motta VRV, Pantoja PC, et al. Actinic keratosis—review for clinical practice. Int J Dermatol. 2019;58:400–407.
3. James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 12th ed. Philadelphia, PA: Elsevier; 2016:676, 680–698.
