Should halo nevi (benign melanocytic lesions) in adults be biopsied?

Management of Halo Nevi in Adults

Halo nevi in adults should be biopsied to exclude melanoma due to the higher risk of malignancy in this age group compared to children and adolescents. 1

Understanding Halo Nevi

Halo nevi (also called Sutton nevi) are benign melanocytic nevi surrounded by a depigmented area resembling a halo. While they are common in children and young adults (mean age of onset around 15 years), their appearance in adults warrants closer attention.

Key characteristics:

• Estimated incidence in the general population is approximately 1% 2
• Typically localized on the back
• May occur as multiple lesions
• Autoimmune response with T lymphocytes playing a key role in nevus cell destruction
• May be associated with autoimmune disorders (vitiligo, Hashimoto thyroiditis, etc.)
• Often detected after intense sun exposure, especially after sunburns 2

Diagnostic Approach for Adults

Clinical Evaluation:

• Complete skin examination is mandatory to detect any other suspicious lesions 3
• Palpation of all regional lymph nodes 3
• Dermoscopic examination may be helpful but should only be performed by those experienced with the technique 3
  • Most common dermoscopic patterns are globular and/or homogeneous in over 80% of halo nevi 4
  • True melanomas with halo-like depigmentation, while rare, will typically display melanoma-specific dermoscopic criteria 4

Biopsy Recommendations:

• For adults with a single halo nevus, excisional biopsy is recommended to exclude melanoma 1
• Complete excision with a narrow rim (2 mm) of normal skin is the standard practice 3
• Excision should be performed with a scalpel (not laser or electrocautery) to preserve histological features 3
• The incision should be elliptical with the long axis parallel to skin lines 3

Special Considerations

Multiple Eruptive Halo Nevi in Adults:

• Particularly concerning in post-adolescent patients
• May indicate underlying malignancy
• One study found significantly higher incidence of melanoma (955 times higher than expected) in adults with multiple eruptive halo nevi 5
• Consider additional workup similar to melanoma patients with unknown primary, including:
  • Complete skin examination
  • Ophthalmologic examination to exclude intraocular melanoma 1
  • Consider advanced imaging in selected cases 5

Histopathological Evaluation:

The histopathological report should include 3:

• Confirmation of melanocytic nature and assessment of malignancy
• Maximum tumor thickness (if applicable)
• Assessment of excision margins
• Level of invasion
• Presence and extent of regression
• Presence and extent of ulceration

Follow-up Recommendations

• For benign halo nevi with clear margins, observation is appropriate 6
• Regular clinical and dermoscopic monitoring with documentation of baseline appearance 6
• Patients should be educated about concerning changes (rapid growth, bleeding, pain, nodule development, ulceration) that warrant prompt evaluation 3

Pitfalls and Caveats

• Diagnostic difficulties may arise in the ultimate phase of regression when melanocytes are diminished or destroyed by immune reaction 7
• Halo phenomenon may occasionally be the first sign of melanoma in a remote location 1
• Digital dermoscopic follow-up has limited value in the diagnosis of halo nevi, as their structural patterns remain unchanged despite considerable changes in area over time 4
• Avoid unnecessary re-excision of clearly benign lesions with mild atypia and clear margins, as this can lead to excessive scarring and patient anxiety 6