# Lentigines (렌티고, 주근깨·검버섯) --- ## 1. Definition   - **Lentigines (렌티고)** are **benign pigmented macules** caused by increased numbers of melanocytes in the basal epidermis. - Unlike freckles (ephelides), lentigines do **not darken significantly with sun exposure** and persist throughout life. --- ## 2. Pathophysiology - **Cellular Basis**: - Proliferation of melanocytes along the basal layer. - Increased melanin production within keratinocytes. - **Molecular Drivers**: - Mutations in **BRAF, NRAS, KIT** implicated in some lentigo variants. - UV exposure → stimulates melanogenesis → especially in solar lentigines. - **Histology**: - Elongated rete ridges. - Basal layer hyperpigmentation. - Increased melanocyte density without atypia. --- ## 3. Types of Lentigines ### A. Lentigo Simplex (단순 렌티고) - Usually arises in childhood. - Small, round/oval, uniformly pigmented macules. - Not related to sun exposure.  ### B. Solar Lentigo (노인성 색소반, 검버섯) - Very common in elderly. - Caused by chronic UV exposure. - Sharply demarcated, tan-to-brown macules on face, hands, arms. - Marker of photodamage and skin aging. ### C. Ink Spot Lentigo (잉크반점 렌티고) - Irregular, sharply defined dark macules. - Benign but clinically striking. ### D. Syndromic Lentigines (증후군성 렌티고) - May occur in **Peutz–Jeghers syndrome (퓨츠-예거스 증후군)**, **LEOPARD syndrome**, **Carney complex**. - Important red flag for systemic disease. --- ## 4. Clinical Features - **Appearance**: Flat, pigmented macules (tan, brown, black). - **Size**: 2 mm to >1 cm. - **Borders**: Sharp, well-defined. - **Symmetry**: Usually uniform in benign lesions. - **Distribution**: Face, dorsum of hands, shoulders, upper back (sun-exposed areas). --- ## 5. Differential Diagnosis - **Freckles (주근깨, ephelides)**: darken with sun, fade in winter; lentigines persist. - **Melanocytic nevus (모반)**: often raised; lentigines remain macular. - **Melasma (기미)**: larger patches, hormonally driven. - **Early melanoma (흑색종)**: irregular color, asymmetry, evolution. --- ## 6. Epidemiology & Prevalence - **Solar lentigines**: - > 90% of individuals over age 60 have them. - Prevalence rises with cumulative UV exposure. - **Lentigo simplex**: Common in children/adolescents; no malignant potential. - More common in lighter phototypes (I–III), but appear across all skin types. --- ## 7. Management ### A. General Principles - Benign → treatment optional, usually cosmetic. - **Primary prevention**: Sun protection, avoidance of tanning beds. ### B. Treatment Options - **Topical depigmenting agents**: hydroquinone, retinoids, azelaic acid. - **Chemical peels**: glycolic acid, trichloroacetic acid (TCA). - **Cryotherapy**: liquid nitrogen (effective for solar lentigines). - **Laser therapy**: - **Q-switched Nd:YAG (532 nm)** or **Q-switched Ruby/Alexandrite** lasers → target melanin. - **Intense pulsed light (IPL)** also effective for photodamaged skin. - **Risks**: PIH, especially in darker skin. --- ## 8. Prognosis - Benign, no malignant transformation. - But **marker of cumulative photodamage** → patients at higher risk for actinic keratoses and skin cancer. - Cosmetic improvement possible, but recurrences common with continued sun exposure. --- ## 9. Clinical Pearls 1. **Lentigines persist; freckles fluctuate.** 2. Solar lentigines are a **UV damage marker**, often coexisting with actinic keratoses. 3. For cosmetic clearance: **Q-switched Nd:YAG (532 nm)** or **IPL** are first-line devices. 4. Always check for syndromic associations if lentigines are multiple and widespread in a young patient. 5. Sun protection is the single most effective long-term management. --- ✅ **Summary for clinical practice:** Lentigines (렌티고, 주근깨·검버섯) are benign pigmented macules caused by melanocyte hyperplasia and increased melanin deposition, commonly induced by chronic sun exposure. They are extremely prevalent in older adults, especially solar lentigines (검버섯). Management is primarily cosmetic—topicals, peels, cryotherapy, or pigment-targeting lasers (Nd:YAG, IPL). Importantly, they serve as a **clinical marker of photodamage and increased skin cancer risk**. ---