The Bottom Line

An excisional biopsy removes an entire skin lesion — not just a sample of it — using a scalpel. The removed tissue is sent to a pathologist for analysis. For many small skin cancers and atypical moles, excision in one visit accomplishes two goals at once: it diagnoses the lesion and removes it completely. The procedure takes about 20–45 minutes under local anesthesia, the wound is closed with stitches, and results are typically available in 5–10 business days.

What Is an Excisional Biopsy?

A biopsy is any procedure that removes tissue from the body so it can be examined under a microscope. There are several types of skin biopsies, and the excisional biopsy is the most thorough: it removes the entire lesion plus a small margin of normal-looking skin around it, all the way down to the fat layer beneath the skin.

This approach is different from:

  • Shave biopsy: A razor-like blade shaves off the surface of a raised lesion (no stitches needed, but only samples part of the depth)
  • Punch biopsy: A small circular blade punches through to the deep dermis (good for flat lesions but only captures a small column of tissue)
  • Incisional biopsy: Only a portion of a large lesion is removed for sampling

Excisional biopsy is preferred when your dermatologist is concerned about melanoma, a deeply invasive growth, or any lesion where complete removal and accurate depth measurement are critical for treatment planning.

When Is an Excisional Biopsy Recommended?

Your dermatologist may recommend excisional biopsy for:

  • Atypical or suspicious moles (melanocytic nevi): Especially if they show multiple concerning features under dermoscopy
  • Suspected melanoma: Excisional biopsy is the preferred diagnostic technique because it captures the full depth, which determines Breslow thickness — a critical number for staging and treatment planning
  • Small basal cell or squamous cell carcinomas: Where excision can be both diagnostic and curative in a single visit
  • Dermatofibromas or other fibrous growths: That extend deep into the skin and need full removal to prevent recurrence
  • Subcutaneous lumps or unusual growths that require full-thickness tissue for accurate diagnosis

What Happens During the Procedure?

Excisional biopsy is performed in the dermatology office under local anesthesia. Here is what to expect step by step:

  • Marking the site: The surgeon draws an ellipse (oval) around the lesion, including the recommended margin of normal skin. An ellipse, rather than a circle, allows the wound edges to come together neatly without puckering.
  • Anesthesia: Lidocaine with epinephrine is injected around (not into) the lesion. You will feel a brief sting, then the area is numb within a minute.
  • Excision: Using a scalpel, the surgeon cuts along the marked ellipse, goes down through the full thickness of skin, and removes the specimen in one piece.
  • Orientation: The specimen is tagged with a suture or marking dye so the pathologist can tell exactly which edge corresponds to which direction on your body. This matters if margins are close and further surgery is needed.
  • Hemostasis: Any bleeding vessels are sealed with light electrocautery or pressure.
  • Closure: The wound is closed in layers — deep absorbable sutures bring the wound together beneath the surface, and surface sutures or staples close the skin. This two-layer closure reduces tension and leads to a flatter scar.
  • Duration: The procedure typically takes 20–45 minutes total.

What Happens to the Tissue?

The specimen is placed in a preservative solution (formalin) and sent to a dermatopathology laboratory. A pathologist processes, sections, and stains the tissue, then examines it under a microscope. The pathology report will tell you:

  • What the lesion is (diagnosis)
  • Whether it is benign (non-cancerous) or malignant (cancerous)
  • If cancerous: the tumor depth, subtype, and whether the margins are clear

Standard turnaround is 5–10 business days. Your dermatologist will contact you with the results and discuss whether any further treatment is needed.

Recovery and Wound Care

  • First 24 hours: Keep the bandage in place and dry. Some mild throbbing as the anesthetic wears off is normal.
  • Daily care: Gently clean the wound with mild soap and water, apply a thin coat of petroleum jelly, and cover with a fresh bandage. Keeping the wound moist speeds healing and reduces scarring.
  • Activity restrictions: Avoid strenuous exercise or heavy lifting for 1–2 weeks to prevent the wound from reopening.
  • Suture removal: Face and neck sutures are removed at 5–7 days; trunk and scalp at 10–14 days; legs and feet at 14–21 days.
  • Sun protection: Once healed, protect the scar from direct sun exposure for at least 6–12 months. UV exposure darkens healing scars and slows fading.

When to See a Dermatologist

  • You have a mole or skin growth that is new, changing, itching, or bleeding
  • Your dermatologist has recommended a biopsy but you have questions about which type is right for your lesion
  • You received biopsy results showing a dysplastic (atypical) mole and were told you need a wider excision
  • Your surgical wound is showing signs of infection: increasing redness, swelling, warmth, pus, or fever above 101°F (38.3°C)
  • Your stitches feel very tight or the wound edges are separating

Frequently Asked Questions

Why excise the whole lesion instead of just taking a sample?

For lesions suspected to be melanoma, taking only part of the lesion can miss the deepest portion of the tumor — and Breslow thickness (how deep it goes) is the single most important factor in staging and treatment decisions. A partial sample could give an artificially thin measurement and lead to under-treatment. Full excision also eliminates the need for a second procedure if the lesion turns out to be benign or a low-risk cancer that was already fully removed.

What if the pathology shows a close or positive margin?

A “positive margin” means cancer cells reach or are very near the cut edge of the specimen. For melanoma, this means a wider re-excision following established margin guidelines will be recommended. For basal cell carcinoma, options include re-excision or Mohs micrographic surgery (which checks 100% of the margins). Your dermatologist will review the report and recommend the appropriate next step.

Will the excisional biopsy leave a scar?

Yes — any full-thickness incision leaves a scar. The scar from an excisional biopsy is a thin line, typically two to three times the length of the original lesion. On the face, careful suture technique and post-op scar care (silicone gel, sunscreen) can minimize appearance. Scars continue to improve for up to 18 months.

Is excisional biopsy the same as Mohs surgery?

No. In standard excision the specimen is processed in a lab over several days, and only a representative sample of the margins is examined. Mohs micrographic surgery processes tissue immediately in the clinic and examines 100% of the surgical margins the same day. Mohs is reserved for skin cancers in high-risk locations or aggressive types, where it offers superior cure rates.

References

  1. Swetter SM, et al. Biopsy of pigmented lesions: excisional versus other techniques. J Am Acad Dermatol. 2019;80(2):e31-e33.
  2. National Comprehensive Cancer Network (NCCN). Melanoma Guidelines: Biopsy Technique. Version 2024.
  3. Coit DG, et al. NCCN Guidelines Insights: Melanoma, Version 3.2016. J Natl Compr Canc Netw. 2016;14(8):945-954.
  4. American Academy of Dermatology. Clinical Guidelines for Biopsy of Pigmented Lesions. AAD.org.

Trusted Resources

Always consult a board-certified dermatologist for diagnosis and treatment of suspicious skin lesions. This article is for educational purposes only and does not replace professional medical advice.