# 1.2 Distinction between Pigmented vs. Non-Pigmented Lesions _(색소성 vs 비색소성 병변)_ --- ## A. Core Concept - **Pigmented lesions (색소성 병변)**: Lesions in which **melanin (or other pigments)** is the primary cause of visible color. - **Non-pigmented lesions (비색소성 병변)**: Lesions where color/appearance is not primarily due to melanin, but rather keratinocyte proliferation, vascular changes, or other processes. --- ## B. Pigmented Lesions (색소성 병변) ### 1. Origin - Due to **melanocyte proliferation** or **melanin accumulation**. - May involve epidermis, dermis, or both. ### 2. Examples - **[[Melanocytic nevi (모반)]]**: Junctional, compound, intradermal. - **[[Lentigines (렌티고, 주근깨·검버섯)]]**: Solar lentigo, lentigo simplex. - **[[Melasma (기미)]]**. - **[[Café-au-lait macules (카페오레반점)]]**. - **[[Post-inflammatory hyperpigmentation, PIH (염증후 과색소침착)]]**. - **[[Malignant melanoma (흑색종)]]**. ### 3. Clinical Features - Brown/black/blue hues depending on depth: - **Epidermal pigment** → brown, sharply demarcated. - **Dermal pigment** → blue-gray (Tyndall effect). - Usually symmetric if benign; irregular if malignant. ### 4. Laser Relevance - Best treated with **pigment-selective lasers** (e.g., Q-switched or Nd:YAG 532/1064 nm). - Risk: PIH in darker phototypes. - Must **rule out melanoma** before laser therapy. --- ## C. Non-Pigmented Lesions (비색소성 병변) ### 1. Origin - Not due to melanin; instead from keratinocytes, blood vessels, connective tissue, or adnexal structures. ### 2. Examples - **[[Seborrheic keratoses (지루각화증)]]**. - **[[Actinic keratoses (광선각화증)]]**. - **Skin tags (연성 섬유종, acrochordons)**. - **Warts (사마귀, HPV 관련)**. - **Hemangiomas (혈관종)**. - **Basal cell carcinoma (기저세포암, 일부 형태)**. ### 3. Clinical Features - Flesh-colored, erythematous, or waxy brown (but pigment is from keratin, not melanin). - Surface may be verrucous, scaly, friable. - Not following pigment network patterns on dermoscopy. ### 4. Laser Relevance - Require **ablative lasers (CO₂, Er:YAG)** or other destructive modalities. - Pigment-targeting lasers (Nd:YAG) ineffective since melanin not primary chromophore. --- ## D. Dermoscopic Differentiation |Feature|Pigmented Lesions (색소성)|Non-Pigmented Lesions (비색소성)| |---|---|---| |**Primary chromophore**|Melanin|Keratin, vessels, collagen| |**Color**|Brown, black, blue, gray|Flesh-colored, pink, red, yellow, waxy brown| |**Pattern**|Pigment network, dots, globules|Milia-like cysts, vascular patterns| |**Examples**|Nevi, lentigo, melanoma, PIH|Seborrheic keratosis, actinic keratosis, warts, hemangioma| |**Preferred Laser**|Nd:YAG, Q-switched pigment lasers|CO₂ laser, Er:YAG laser, vascular lasers (PDL for hemangioma)| --- ## E. Clinical Algorithm 1. **Initial inspection**: Is the lesion truly pigmented (brown/black/blue) or flesh-colored? 2. **Dermoscopy**: Look for pigment network → suggests melanocytic origin. 3. **Check for atypia**: Asymmetry, irregular borders, variegated colors → biopsy if suspicious. 4. **Decide laser type**: - Pigmented → Nd:YAG, pigment-specific. - Non-pigmented → CO₂ ablation or vascular laser. --- ## F. Clinical Pearl - **“All that is brown is not melanocytic.”** - Seborrheic keratoses and even crusted actinic keratoses can look pigmented but are non-melanocytic. - Histology or dermoscopy helps prevent misclassification. --- ✅ **Key Takeaway** - The **distinction between pigmented and non-pigmented lesions** is fundamental: it guides whether to use **melanin-targeting lasers (Nd:YAG)** vs. **tissue-ablative lasers (CO₂)**. - Always confirm with dermoscopy and clinical judgment before proceeding to cosmetic removal. --- 원장님, 원하시면 제가 이 부분을 **“레이저 선택 알고리즘 Flowchart (text 기반)”**으로 정리해드려서 임상 적용하기 쉽게 만들어드릴 수도 있습니다. 그렇게 진행해드릴까요?