Will a mole regrow if a dermatologist performs a scraping biopsy and removes most of it?

Will a Mole Regrow After Scraping Biopsy?

Yes, a mole can regrow if the dermatologist performed a scraping (shave) biopsy that removed most but not all of it, because melanocytic cells remaining in the deeper layers of skin can regenerate the lesion. However, the clinical significance and management depend entirely on whether the mole was benign or atypical.

Understanding What Happens After Partial Removal

Benign Moles

• Benign melanocytic nevi can recur if melanocytic cells remain in the deeper dermis after superficial removal 1
• The recurrence is typically benign and represents regrowth from residual nevus cells, not malignant transformation 2
• This phenomenon can create a "pseudomelanoma" appearance both clinically and pathologically, which may cause diagnostic confusion 1

Atypical (Dysplastic) Nevi

• For mildly to moderately atypical nevi with positive margins after shave biopsy, observation is acceptable rather than re-excision, as studies show very low recurrence rates (approximately 3.6% over 2 years) and no melanoma development in incompletely excised atypical nevi followed for 5+ years 2
• Local recurrence rates are minimal even when margins are positive after initial biopsy 2
• Severely atypical nevi should be completely excised due to higher melanoma association, and observation alone is not recommended 2

Why Scraping/Shave Biopsies Are Problematic

Diagnostic Limitations

• Shave biopsies should be avoided for suspicious lesions because they may lead to incorrect diagnosis due to sampling error and make accurate pathological staging impossible 1
• Partial removal compromises assessment of critical features like maximum tumor thickness (Breslow depth), which is essential for melanoma staging 3
• Complete excisional biopsy is the gold standard for any suspicious pigmented lesion to allow comprehensive histological evaluation 3, 1

Technical Considerations

• A scalpel rather than laser or electro-coagulation should be used for excision to avoid tissue destruction that compromises diagnosis 3
• The entire lesion must be examined to assess all histological parameters, particularly maximum thickness 3

What Should Happen Next

If the Pathology Shows a Benign Nevus

• No further treatment is needed if the lesion was completely benign 3
• Simple observation is appropriate even if some nevus cells remain 2

If the Pathology Shows Mild to Moderate Atypia

• Observation with clinical and dermoscopic follow-up is acceptable for mildly atypical nevi, particularly when the patient has multiple other atypical nevi 2
• Conservative re-excision with 2-5 mm margins is preferred if this is the patient's only atypical nevus or if there is moderate atypia 2
• Regular self-examination should be taught 2

If the Pathology Shows Severe Atypia or Melanoma

• Complete surgical excision is mandatory for severely atypical nevi 2
• For melanoma, wide excision with appropriate margins based on tumor thickness is required, and any residual nevus must be completely removed 1

Warning Signs That Require Immediate Re-evaluation

Watch for these concerning changes in any residual or recurrent mole 2:

• Rapid growth or darkening
• Bleeding or ulceration
• Development of nodules or color variegation

Common Pitfalls to Avoid

• Never perform diagnostic shave biopsies on suspicious lesions as this compromises accurate diagnosis and staging 1
• Avoid partial removal of melanocytic nevi as this creates pseudomelanoma patterns that confound diagnosis 1
• Don't assume all recurrent pigmentation after biopsy represents melanoma—it may simply be benign nevus regrowth 2, 1

Bottom Line

The mole can regrow from residual cells, but whether this matters depends on the pathology results. For benign nevi, regrowth is clinically insignificant. For mildly atypical nevi, observation is often sufficient. For severely atypical lesions or melanoma, complete excision should have been performed initially, and any residual tissue requires definitive removal 2, 1.