How do I evaluate a mole using the ABCDE criteria?

Evaluating Moles Using the ABCDE Criteria

Use the ABCDE criteria systematically to identify suspicious pigmented lesions: Asymmetry, Border irregularity, Color heterogeneity, Diameter (though many melanomas are <5mm), and Evolution (change over time), with Evolution being the most critical criterion for detecting rapidly growing melanomas. 1, 2

The ABCDE Components

A - Asymmetry

• Asymmetry of contour means one half of the lesion does not match the other half, present in approximately 65% of melanomas 2
• Evaluate asymmetry of both the outer shape and differential structures inside the lesion in at least one axis 3

B - Border Irregularity

• Look for uneven, notched, or scalloped edges, as regular borders are found in only 12% of melanomas 2
• Abrupt cutoff of pigment network at the border in at least one quarter of the circumference is particularly concerning 3

C - Color Heterogeneity

• Multiple colors or uneven distribution of pigmentation within a single lesion is a key warning sign 2
• Three or more colors within a lesion significantly increases suspicion 3

D - Diameter

• The traditional 6mm threshold is outdated and unreliable, as many primary melanomas today have a diameter of <5mm 1, 2
• Approximately 38% of all melanomas are ≤6mm in diameter, violating this criterion 2
• Do not rely on diameter alone to rule out melanoma 4

E - Evolution (Most Critical)

• Evolution—changes in colors, elevation, or size over time—is the most important criterion because it helps identify rapidly growing amelanotic melanomas 1, 2
• Any noticed change in the last 3 months warrants immediate evaluation 3

Critical Limitations and Complementary Approaches

When ABCDE Criteria Fail

• Nodular melanomas often present as symmetric, dome-shaped nodules with regular borders and uniform color, lacking the asymmetry, border irregularity, and color variegation typical of superficial spreading melanoma 2
• Nodular melanomas grow rapidly in elevation rather than diameter, making the "E" criterion critical 2

The "Ugly Duckling" Concept

• The "ugly duckling" concept is more valuable than ABCDE criteria for nodular and desmoplastic subtypes, as it identifies lesions that don't fit the patient's overall nevus pattern 2
• Melanomas often do not resemble other nevi in the same individual 2

Enhanced Diagnostic Accuracy

Dermoscopy

• Dermoscopy by an experienced physician enhances diagnostic accuracy beyond clinical examination alone 1, 5
• Dermoscopy improves clinical diagnostic sensitivity by 10% to 27% 3

Complete Examination Requirements

• Complete skin examination is mandatory, including full body skin surface inspection, regional lymph node palpation, and documentation of lesion site, size, and characteristics 6

When to Biopsy

Low Threshold Approach

• Maintain a low threshold for biopsy when encountering any rapidly growing nodular lesion, regardless of symmetry or border regularity 2
• Biopsy any lesion that appears "funny looking" or doesn't show typical benign features, even if it doesn't meet ABCDE criteria 7

Biopsy Technique

• Full-thickness excisional biopsy with a 2-5mm clinical margin of normal skin laterally and a cuff of subdermal fat is the only acceptable approach for suspected melanoma 6
• The specimen must be adequate to determine Breslow thickness, the most important prognostic parameter 4

Common Pitfalls to Avoid

• Do not dismiss small lesions (<6mm) as benign based on diameter alone 1, 2
• Do not overlook amelanotic (non-pigmented) melanomas that may only show evolution without other ABCDE features 1
• Do not rely solely on ABCDE criteria for nodular melanomas, which may appear symmetric and regular 2
• Maintain high suspicion in high-risk populations including those with prior skin cancer, immunosuppression, or genetic syndromes 6