Should I refer a patient with a congenital melanocytic nevus (CMN) to a dermatologist (derm) as a general practitioner (GP)?

Referral Guidelines for Congenital Melanocytic Nevi

Yes, you should refer patients with large, giant, or multiple congenital melanocytic nevi (CMN) of any size to a dermatologist, while solitary small and medium CMN without concerning features can be managed by primary care providers. 1

Referral Decision Algorithm Based on CMN Characteristics

Immediate Dermatology Referral Required:

• Large CMN (>20 cm projected adult size)
• Giant CMN (>40 cm projected adult size)
• Multiple CMN of any size
• Any CMN with concerning features:
  • Color variation
  • Nodules
  • Symptoms (pain, bleeding, itching)
  • Rapid growth
  • Ulceration
  • Location in cosmetically sensitive areas

Referral Can Be Delayed or Managed by GP:

• Solitary small CMN (<1.5 cm)
• Solitary medium CMN (1.5-20 cm)
• No concerning features present

Risk Assessment

The risk of melanoma development varies significantly based on CMN characteristics:

• Giant CMN (>40 cm): Highest risk (1-3.6%)
• Multiple CMN with a giant CMN >60 cm: 8% risk of melanoma 1
• Small to medium solitary CMN: Lower risk (0.7-1.7%)

Melanoma risk is significantly higher in patients with:

• Projected adult size >40 cm
• Numerous "satellite" nevi
• Trunk location
• Multiple medium-sized CMN 1

Monitoring Recommendations

For High-Risk CMN (Large, Giant, Multiple):

• Initial evaluation by dermatologist in neonatal period
• Follow closely during infancy with visits every 3 months
• Yearly dermatologist evaluation minimum after first year
• Regular palpation of CMN and regional lymph nodes
• MRI screening for patients with multiple medium CMN, ≥10 "satellite" lesions, or giant CMN to evaluate for neurocutaneous melanosis (NCM)

For Lower-Risk CMN (Small, Medium, Solitary):

• Can be monitored by GP
• Regular visual inspection and palpation
• Patient/caregiver education on concerning changes
• No routine MRI screening needed unless neurological symptoms develop 1

Important Clinical Pearls

1. Palpation is crucial: Melanoma in CMN can present as deep nodules without overlying color change 1

2. Monitor for these changes that require prompt dermatology evaluation:

   • Rapid growth
   • Bleeding
   • Pain
   • Development of a lump or nodule
   • Ulceration 1

3. Proliferative nodules can develop within CMN and may mimic melanoma clinically and histologically, but are typically benign 2

4. Pregnancy can affect CMN: Increased estrogen levels during pregnancy may cause CMN to increase in size and potentially increase risk of malignant transformation 3

5. Avoid shave biopsies of suspicious pigmented lesions as they may underestimate depth and lead to inappropriate management 4

Patient Education

Instruct patients/caregivers to:

• Monitor nevi visually and with palpation
• Report concerning changes promptly
• Follow sun protection guidelines (sunscreen, protective clothing, seeking shade)
• Understand that some changes in CMN are normal (color variation, texture changes) 1

By following these guidelines, GPs can appropriately triage patients with CMN, ensuring those at higher risk receive timely specialist evaluation while avoiding unnecessary referrals for lower-risk lesions.