ABCDE Melanoma Rule

The ABCDE criteria provide a clinical decision framework for evaluating pigmented lesions for melanoma: Asymmetry (one half does not mirror the other), Border irregularity (scalloped, notched, or poorly defined margins), Color variation (multiple shades of brown, black, red, white, or blue within a single lesion reflecting varying depths of melanocyte invasion and regression), Diameter greater than 6 mm (though melanomas can be smaller at initial presentation), and Evolving (any change in size, shape, color, elevation, or new symptoms such as bleeding, itching, or crusting). The clinician applies these criteria alongside dermoscopic features (atypical pigment network, blue-white veil, regression structures, irregular dots/globules, atypical vascular patterns) to determine biopsy necessity. Melanoma staging uses the AJCC TNM system: Breslow thickness (depth of invasion in millimeters -- the single most important prognostic factor), ulceration status, mitotic rate, Clark level, sentinel lymph node status, and distant metastases. The clinician performs full-body skin examinations, identifies high-risk patients (fair skin, history of blistering sunburns, family history of melanoma, atypical mole syndrome with more than 50 nevi, immunosuppression), counsels on photoprotection, and determines referral urgency based on clinical...