Skin biopsy (punch / excisional)

Category: Biopsies, Lab & Pathology Tests · All biopsies, lab & pathology tests

What it is

A skin biopsy removes a small sample of skin for examination under the microscope. A punch biopsy uses a circular blade to take a small full-thickness core; an excisional biopsy removes a whole lesion; a shave biopsy skims a surface lesion; an incisional biopsy samples part of a larger lesion.

Why it is done

It diagnoses rashes that are not responding as expected, blistering diseases, skin infections and — most commonly — skin lesions that might be cancerous, including suspected melanoma and other skin cancers.

How to prepare

Tell the clinician about blood thinners, allergies (including to local anaesthetic and dressings), pacemakers (if cautery is used) and any tendency to keloid scarring. No fasting is needed.

What happens during the procedure

The area is numbed with a small injection (brief sting), then the sample is taken in seconds (punch) or minutes (excision). One or two stitches may close the site and a dressing is applied. The specimen goes into a labelled pot for the laboratory.

Afterwards — recovery & results

Keep the dressing dry for the first day or two as instructed, then care for the wound as advised; stitches (if not dissolvable) are removed at about a week (longer on the back or legs). Results usually take two to four weeks — your clinic explains how they will reach you and what happens next for each possible result.

Risks & considerations

Risks include bleeding, infection, a scar (unavoidable, usually small), altered sensation near the site, and rarely the sample being non-diagnostic, occasionally requiring a further biopsy. Excision of a melanoma-suspicious lesion is planned with margins so the biopsy doubles as treatment where possible.

Frequently asked questions

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