Lesion
Any area that looks different from the surrounding normal tissue — a deliberately neutral word.
What it means
Any area of tissue that looks different from what surrounds it. A freckle is a skin lesion. So is a bruise, a cyst, a scar, an ulcer and a tumour.
It is deliberately neutral, and that is the entire point. A radiologist describing a "lesion" is saying "something is here that is not the same as the tissue around it" without committing to what it is.
It is not a euphemism for cancer, and it is read that way constantly.
In practice
Throughout radiology reports, dermatology letters and operation notes.
Usually qualified — "a well-defined lesion", "a cystic lesion", "a benign-appearing lesion" — and those qualifiers carry most of the meaning.
Why it matters
Read the words around it rather than the word itself. "Well-defined", "cystic" and "stable compared with previous imaging" are all reassuring; "irregular", "enhancing" and "increased in size" are not.
Ask what it is thought to be, and whether anything needs doing. Those two answers matter and the word "lesion" gives you neither.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026