What is the appropriate approach to evaluating and managing a skin lesion?

Approach to Skin Lesion Evaluation and Management

Begin with a focused history emphasizing lesion duration, evolution, symptoms (pain, bleeding, pruritus), sun exposure history, personal or family history of skin cancer, and immunosuppression status, followed by systematic examination using the ABCDE criteria for melanoma and assessment for features suggesting malignancy. 1

Critical Historical Elements

• Document the timeline of lesion appearance and any changes in size, color, shape, or symptoms over weeks to months, as evolution is a key indicator of malignancy 1
• Identify high-risk factors including fair skin (Fitzpatrick types I-II), history of frequent sunburns, age over 50, male sex, previous skin cancers, family history of melanoma (especially ≥2 cases), atypical mole syndrome, giant congenital nevi, organ transplantation, and immunosuppression 1
• Obtain complete medication history to identify potential drug-induced lesions, particularly if blistering or widespread erythema is present 1

Physical Examination Approach

For Solitary or Few Lesions

• Apply the ABCDE rule for melanoma detection: Asymmetry, Border irregularity, Color heterogeneity (multiple colors within lesion), Diameter >6 mm, and Evolution (recent changes in size, shape, color, elevation, or symptoms) 1
• Use the "ugly duckling" sign to identify pigmented lesions that appear different from the patient's other moles, as this may indicate melanoma 1
• Examine for basal cell carcinoma features: pearly, translucent papules or nodules with telangiectasias, particularly in the "H-zone" of the face (central face, periorbital, nose, ears), noting that lesions ≥6 mm in high-risk locations or ≥10 mm in moderate-risk locations have higher recurrence rates 1
• Assess for squamous cell carcinoma characteristics: hyperkeratotic, crusted, or ulcerated lesions on sun-exposed areas, particularly non-healing wounds lasting >4 weeks 1

For Diffuse or Multiple Lesions

• Measure body surface area involvement using the Lund and Browder chart, separately documenting percentage of erythema and epidermal detachment, as >10% BSA involvement with blistering requires immediate hospitalization 1, 2
• Examine all mucosal surfaces (oral, ocular, genital, perianal) for erosions or blistering, as mucosal involvement suggests Stevens-Johnson syndrome/toxic epidermal necrolysis or immunobullous disease 1, 2
• Perform complete skin examination of all body sites including scalp, interdigital spaces, and nails, as patients with one skin cancer often have concurrent lesions and are at increased risk for melanoma 1

Diagnostic Procedures

Biopsy Technique

• Perform complete excisional biopsy with 2 mm clinical margin and cuff of subcutaneous fat for suspected melanoma, as this allows accurate Breslow thickness measurement and definitive diagnosis 1
• Never perform shave, punch, or incisional biopsies of suspected melanoma (except for lentigo maligna on face or acral melanoma where complete excision is impractical), as partial sampling causes diagnostic errors and prevents accurate staging 1
• For suspected basal cell carcinoma, ensure biopsy includes deep reticular dermis, as infiltrative histology may be present only at deeper margins and superficial biopsies frequently miss this component 1
• For diffuse blistering eruptions, obtain two biopsies: one from lesional skin for routine histopathology and one from perilesional skin sent unfixed for direct immunofluorescence to distinguish immunobullous disorders from drug reactions 1, 2

Laboratory Evaluation

• Order complete blood count, comprehensive metabolic panel, liver function tests, and lactate dehydrogenase for melanoma staging 1
• For diffuse eruptions with systemic symptoms, add erythrocyte sedimentation rate, C-reactive protein, coagulation studies, and mycoplasma serology 1, 2

Imaging Studies

• Perform imaging only when clinically indicated: for melanoma with Breslow thickness >1 mm, use chest X-ray and abdominal ultrasound; for suspected bone involvement, perineural invasion, or deep soft tissue involvement in basal cell carcinoma, use MRI (preferred over CT for perineural disease) 1
• PET scanning is not useful for initial staging of clinically localized melanoma 1

Risk Stratification and Referral

High-Risk Features Requiring Specialist Referral

• Melanoma: any lesion meeting ABCDE criteria, diameter >6 mm with recent changes, or "ugly duckling" appearance 1
• Basal cell carcinoma: location in H-zone of face with diameter ≥6 mm, moderate-risk location with diameter ≥10 mm, infiltrative or morpheaform histology, perineural invasion, or recurrent tumors 1
• Squamous cell carcinoma: diameter ≥5 cm, depth >4 mm, poorly differentiated histology, perineural invasion, or location on ear or lip 1
• Diffuse eruptions: >10% BSA involvement, any mucosal involvement with blistering, or systemic symptoms requiring immediate dermatology consultation or hospital admission 1, 2

Surveillance Recommendations

• For patients with atypical mole syndrome, previous melanoma, or organ transplant recipients, teach monthly self-examination and provide written information with images 1
• For recessive dystrophic epidermolysis bullosa, perform full skin examination every 3-6 months starting at age 10 years; for other high-risk genodermatoses, begin surveillance at age 20 years with 6-12 month intervals 1
• For family history of ≥3 melanomas or melanoma plus pancreatic cancer, refer to clinical genetics for counseling 1

Management of Specific Lesions

Benign Lesions

• Seborrheic keratoses, cherry angiomas, and dermatofibromas require no treatment unless symptomatic, bleeding, or changing 3
• Acrochordons (skin tags) can be removed by scissor excision, shave excision, electrodesiccation, or cryosurgery if symptomatic or cosmetically concerning 3
• Lipomas require excision only if symptomatic, growing, or causing functional impairment 3

Premalignant Lesions

• For actinic keratosis, apply imiquimod cream 2 times per week for 16 weeks to a 25 cm² treatment area, applying before sleep for 8 hours then washing off 4
• Keratoacanthomas require early simple excision due to resemblance to squamous cell carcinoma 3

Malignant Lesions

• For superficial basal cell carcinoma (biopsy-confirmed, ≤2 cm diameter, trunk/neck/extremities excluding hands/feet), apply imiquimod cream 5 times per week for 6 weeks to tumor plus 1 cm margin, before sleep for 8 hours 4
• For melanoma, perform wide excision with margins of 1 cm for Breslow thickness 1-2 mm and 2-3 cm for thicker tumors 1
• Routine elective lymphadenectomy is not recommended; sentinel lymph node biopsy should only be performed by experienced teams 1

Critical Pitfalls to Avoid

• Do not assume benign diagnosis based on patient age, skin type, or lesion location alone, as melanoma occurs in all demographics and acral lentiginous melanoma affects darker-skinned individuals 1
• Do not delay biopsy of suspicious lesions in high-risk patients (immunosuppressed, previous skin cancer, strong family history), as these populations have difficult-to-assess lesions requiring low threshold for biopsy 1
• Do not extend imiquimod treatment beyond recommended duration (16 weeks for actinic keratosis, 6 weeks for superficial basal cell carcinoma) due to missed doses or rest periods 4
• Do not assess treatment response until local skin reactions have resolved (typically 8-12 weeks post-treatment for imiquimod), and perform biopsy if clinical evidence of persistent tumor remains 4