Nevus & Melanoma

Benign Nevus "Tahi Lalat" (Common Mole): A circumscribed, pigmented macule, papule, or plaque. Symmetry and stability are the hallmarks of benignity.

Nevus Pigmentosus: A specific type of melanocytic nevus containing pigment-producing cells. These range from flat junctional nevi to raised compound or intradermal nevi (which may be skin-colored or hairy).

Classic Clues for Benignity:

• Symmetry: One half matches the other perfectly.
• Regular Borders: Smooth, well-demarcated edges.
• Uniform Color: Evenly distributed pigment.
• Stability: No rapid change in size, shape, or color.

Malignant Melanoma

The ABCDE Rule:

• A - Asymmetry: One half doesn't match the other.
• B - Border: Ragged, blurred, or notched edges.
• C - Color: Varied shades of brown, black, red, or blue.
• D - Diameter: Greater than 6mm.
• E - Evolving: Any rapid change in size, shape, or color.

Bedside Diagnostic Pearl:

Always look for the "Ugly Duckling"—a lesion that stands out as being different from the patient's other moles. This is a highly sensitive clinical marker for melanoma.

Clinical Actions:

• Monitoring: Photography and serial monitoring for stable, benign nevi.
• Urgent Referral: Any lesion meeting ABCDE criteria or a positive Ugly Duckling sign.
• Excisional Biopsy: Standard of care for suspicious lesions. Send for HPE (Histopathology).
• Shave Excision: Primarily for cosmetic removal of raised intradermal nevi.

⚠️ Clinical Pearl: All removed pigmented lesions, even those removed for purely cosmetic reasons, MUST be sent for HPE to rule out occult malignancy.