Surgical margin

The rim of normal-looking tissue removed around a tumour so that its microscopic extensions are included. The clinical margin is measured on the skin before excision; the histological margin is the distance from the tumour to the cut edge under the microscope, usually reported as clear (at least 1 mm), close (under 1 mm) or involved.

Related terms

• Condition

  Basal cell carcinoma

  The most common skin cancer, arising from the basal cells of the epidermis. It grows slowly, is caused mainly by sun exposure, and very rarely spreads elsewhere, but it keeps invading local tissue if untreated. Usually cured by excision with a margin of normal skin.

• Condition

  Squamous cell carcinoma

  The second most common skin cancer, arising from the keratinocytes of the epidermis. It grows faster than basal cell carcinoma and spreads to lymph nodes in a small proportion of cases, particularly when large, thick, on the ear or lip, or in immunosuppressed people. Most are cured by excision.

Articles mentioning this term

1. Patient information · 26 September 2026

   Melanoma surgery

   Wide local excision and sentinel node biopsy after melanoma: why the margin follows Breslow thickness, what happens on the day, the risks and follow-up.

2. Patient information · 26 September 2026

   Skin cancer surgery

   What basal cell and squamous cell carcinoma are, why excision is the usual treatment, what margins mean, how wounds are closed, and what recovery involves.

← Back to glossary