Dermatology
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21 Aug 202611 min read
Lesion
Pronounced LEE-zhun
Also known as Abnormal area, Focal abnormality
A lesion is any area of tissue that is damaged or abnormal — a patch, a lump, an ulcer, a scar or a spot seen on a scan. The word describes that something is there without saying what it is or whether it matters.
It is a deliberately neutral term, and the neutrality is the point. When a radiologist writes that a scan shows a lesion in the liver, they are describing an area that differs from the tissue around it and declining to guess further. A mouth ulcer is a lesion. A birthmark is a lesion. So is a tumour. Nothing about the word implies cancer, and reading it that way causes a great deal of unnecessary fear.
How a lesion is described
- Site and size, in millimetres or centimetres, which is what allows the next scan to say whether anything has changed.
- Margins — well-defined and smooth, which tends to reassure, or irregular and infiltrating, which does not.
- Number — solitary or multiple, since multiple lesions suggest a different set of causes.
- Behaviour with contrast on a or , which reflects the blood supply and often narrows the possibilities considerably.
- Change over time, which is frequently the most informative feature of all and the reason a repeat scan is sometimes wiser than an immediate procedure.
Many lesions found by accident during a scan for something else are of no consequence — simple cysts, small haemangiomas, benign nodules — and are so common that radiologists have a word for them, incidentalomas. The reasonable next step depends on how the lesion looks and on the person it is in, and the honest answer is often a repeat scan in six or twelve months rather than immediate action. Where the appearance is uncertain or the risk is real, a is what converts a lesion into a diagnosis: or , and of what kind.
Where this comes up
Related terms
- BiopsyTissue sampling, Histopathology sampleA biopsy is the removal of a small piece of tissue so that it can be examined under a microscope. It is the test that settles what a lump, an ulcer or an abnormal patch actually is, when scans and blood tests can only suggest.
- BenignNon-cancerous, Not malignantBenign describes a growth or a finding that is not cancer: it stays where it started, does not invade surrounding tissue and does not spread elsewhere in the body. Benign is not always the same as harmless.
- MalignantCancerousMalignant describes a growth that can invade the tissue around it and spread to other parts of the body. It is the opposite of benign, which stays where it started.
- EczemaAtopic dermatitis, DermatitisEczema is a long-term condition in which the skin barrier is weak and inflamed, leaving skin dry, itchy and prone to red, cracked or weeping patches. It runs in families alongside asthma and hay fever, and it is controlled rather than cured.