## Why "Increased risk of melanoma and warrants urgent excisional biopsy" is right The feature marked **C** — color variegation (multiple colors within a single lesion: black, brown, tan, red, white, blue) — is one of the five cardinal ABCDE features of melanoma as defined in Robbins 10e Ch 25 and Harrison 21e Ch 75. The presence of variegated color indicates heterogeneous melanin deposition and cellular atypia, reflecting dysplastic changes and increased risk of malignant transformation. This finding alone, especially in combination with other ABCDE features, mandates urgent excisional biopsy with adequate margins (typically 5 mm for suspected in situ lesions, 1 cm for ≤1 mm thickness) to establish diagnosis and determine Breslow depth, which is the primary prognostic determinant. ## Why each distractor is wrong - **Benign nevus that requires only clinical observation**: Benign nevi are typically uniform in color (single shade of brown or tan). Variegated color is a hallmark of dysplasia and melanoma, not a benign finding. Observation alone is inappropriate and delays diagnosis. - **Seborrheic keratosis with no malignant potential**: Seborrheic keratoses are benign, waxy, well-demarcated lesions that do not show variegated color or ABCDE features. They have no malignant potential and are clinically distinct from melanoma. - **Solar lentigo that responds to topical hydroquinone**: Solar lentigines are benign, flat, uniform-colored macules on sun-exposed skin. They lack variegation and ABCDE features. Topical hydroquinone is appropriate for lentigines, not for lesions with melanoma features. **High-Yield:** Variegated color (multiple colors in one lesion) is a cardinal ABCDE feature of melanoma — any lesion with this finding requires urgent excisional biopsy, not observation or topical treatment. [cite: Robbins 10e Ch 25; Harrison 21e Ch 75]
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