What is the best way to remove a melanocytic nevus?

Best Method for Removing Melanocytic Nevi

Complete surgical excision with appropriate margins is the recommended first-line approach for removing melanocytic nevi, with the specific technique determined by the type, size, and location of the nevus. 1

Initial Assessment and Diagnosis

• Before removal, any suspicious lesion should be photographed and thoroughly evaluated for concerning features that might suggest melanoma 1
• Complete excisional biopsy is preferred for suspicious lesions to allow for comprehensive histological assessment 1, 2
• Diagnostic shave biopsies should be avoided for suspicious lesions as they may lead to incorrect diagnosis due to sampling error and make accurate pathological staging impossible 1

Removal Techniques Based on Nevus Type

For Benign Melanocytic Nevi

• Small and medium-sized nevi (up to 5 cm):

  • Complete excisional biopsy with 2 mm clinical margins of normal skin and including a cuff of fat is recommended 1, 3
  • The excision should extend to subcutaneous fat to ensure adequate depth for histopathological assessment 2
  • For facial nevi, round excision or punch excision may provide better cosmetic results than conventional fusiform excision 4

• Atypical (dysplastic) nevi:

  • For mild to moderate atypia with positive margins after initial biopsy, observation may be acceptable as an alternative to reexcision, with studies showing low short-term recurrence rates 1
  • For severe dysplasia or if the atypical nevus is the only one of its kind, conservative reexcision with 2-5 mm margins is preferred 1
  • Full-thickness surgical excision has a higher clearance rate (87.5%) compared to reshave excision (76.2%) for atypical nevi with positive margins 5

• Large nevi (over 5 cm):

  • May require staged excision or removal with prior use of a tissue expander 3
  • For giant congenital nevi, staged treatment with intermediate thickness skin grafting may be necessary 3

For Suspicious or Confirmed Melanoma

• Surgical excision with histologically negative margins is the first-line treatment 1
• Margins should be based on tumor thickness:
  • In situ: 0.5-1 cm margins 1
  • ≤1.0 mm: 1 cm margins 1
  • 1.0-2.0 mm: 1-2 cm margins 1

  • 2.0 mm: 2 cm margins 1

Special Considerations by Location

• Facial nevi:

  • For benign papular or dome-shaped nevi, round excision may provide superior cosmetic results compared to fusiform or shave excision 4
  • Mohs micrographic surgery or staged excision with permanent sections may be utilized for melanoma in situ, lentigo maligna type, on the face, ears, or scalp 1

• Scalp lesions:

  • Excisional biopsy should include subcutaneous fat to ensure adequate depth 2
  • For suspicious lesions that prove to be melanoma, more aggressive excision should be considered 2

• Subungual lesions:

  • Should be performed by experienced surgeons with adequate exposure of the nail matrix 1
  • Distal phalangeal amputation is generally well-tolerated compared to nail bed excision with skin grafting, which may result in persistent sensitivity issues 1

Alternative Techniques

• Deep shave excision with razor blade technique:

  • May be suitable for macular melanocytic nevi with good cosmetic outcomes 6
  • Studies show 88% complete excision rate with this technique 6

• Laser therapy:

  • Junctional nevi may respond to Q-switched/normal mode pigment lasers 7
  • Compound and dermal nevi may require pulsed ablative lasers (CO2/Er:YAG) 7
  • Should be used with caution as it may not provide adequate histological samples 7

Common Pitfalls to Avoid

• Avoid diagnostic shave biopsies for suspicious lesions as they compromise accurate diagnosis and staging 1
• Avoid partial removal of melanocytic nevi as this may result in pseudomelanoma (clinical and pathological picture resembling melanoma) 1
• Prophylactic excision of small (<5 cm diameter) congenital nevi without suspicious features is not recommended 1
• For melanomas arising in a congenital or atypical nevus, ensure removal of both the melanoma with appropriate margins and the entirety of the residual nevus 1

Follow-up Recommendations

• Patients with atypical mole phenotype or previous melanoma should be taught self-examination 1
• Patients with giant congenital pigmented nevi require long-term follow-up due to increased risk of melanoma 1
• Lifelong follow-up for recurrence and melanoma is warranted in predisposed individuals 7