What are the treatment options for lentigo?

Treatment Options for Lentigo

Complete surgical excision is the recommended first-line treatment for lentigo maligna due to the risk of invasive change, while solar lentigines can be effectively treated with combination therapies or laser-based treatments. 1, 2

Types of Lentigines

• Solar lentigines: Benign hyperpigmented macules that occur on sun-exposed areas, commonly known as "age spots" or "liver spots" 2
• Lentigo maligna: A form of melanoma in situ that occurs on sun-exposed skin, particularly the head and neck areas of older patients 3, 4

Treatment Options for Lentigo Maligna

Surgical Approaches

• Complete surgical excision: The gold standard treatment for lentigo maligna with clear histological margins 1
• Mohs micrographic surgery: Associated with the lowest recurrence rate (4-5%) and recommended for cosmetically sensitive areas 5
• Conventional surgery: Provides good results with recurrence rates of 7-10% 5

Non-Surgical Approaches (for patients where surgery is not feasible)

• Radiotherapy: May be appropriate in selected cases, particularly for elderly patients with comorbidities 1
• Cryotherapy: Can be considered in elderly patients where the risk of progression within their lifespan is low 1
• Topical imiquimod: Has emerged as a treatment option, especially for lentigo maligna, though long-term comparative studies are still needed 1

Important Considerations for Lentigo Maligna

• Excision margins of 0.5 cm are recommended for in situ melanoma, though larger margins may be necessary for large lentigo maligna to achieve histologically negative margins 1
• The risk of progression to invasive melanoma (lentigo maligna melanoma) is poorly established but remains a concern 1
• Local recurrence of lentigo maligna is common due to a "field effect" where atypical melanocytes extend laterally beyond clinically detectable borders 1
• If non-surgical treatment is chosen, the reason should be clearly documented 1

Treatment Options for Solar Lentigines

Topical Treatments

• Hydroquinone 4%: FDA-approved for gradual bleaching of hyperpigmented skin conditions including senile lentigines 6
  • Requires sunscreen use during treatment to prevent repigmentation 6
  • Should be tested on a small area first to check for skin sensitivity 6

Physical Therapies

• Laser-based treatments: 43% complete response rate, with 23% experiencing adverse events 2
• Combination-based treatments: Highest efficacy with 65% complete response rate, though 39% experience adverse events 2
• Cryotherapy: Traditional first-line treatment but shows lower efficacy (15% complete response) compared to newer modalities 2
• Chemical peels: 6% complete response rate with 19% experiencing adverse events 2

Treatment Algorithm

1. Diagnosis confirmation:

   • Distinguish between solar lentigo and lentigo maligna through clinical examination and biopsy if necessary 1

2. For confirmed lentigo maligna:

   • First choice: Complete surgical excision with 0.5 cm margins 1
   • If surgery contraindicated: Consider radiotherapy, cryotherapy, or topical imiquimod based on patient factors 1

3. For solar lentigines:

   • First choice: Combination therapy (highest efficacy) or laser-based treatments 2
   • Alternative: Topical hydroquinone 4% with strict sun protection 6

Pitfalls and Caveats

• Lentigo maligna can be misdiagnosed as a benign solar lentigo, leading to inadequate treatment and potential progression to invasive melanoma 3, 4
• Sampling problems with biopsies may mean they are not representative of the whole lesion 1
• Recurrence of lentigo maligna is common due to subclinical extension beyond visible margins 1, 5
• Hydroquinone requires careful patient monitoring and strict sun avoidance to prevent repigmentation 6
• Patients with a history of lentigo maligna melanoma have a 35% risk of developing another cutaneous malignancy within 5 years 1