The short answer
The Bethesda system is a standard way to report thyroid needle biopsy results in six categories. A category is an estimate for one nodule, not a diagnosis. Your next step depends on the category, your ultrasound, and your specialist.
A Bethesda category is a report label for one nodule, not a diagnosis.
The system has six categories, and its third edition was published in 2023.
The National Cancer Institute advises asking to have biopsy samples checked by a pathologist experienced with thyroid cancer.
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The whole article, with every detail and caution.
This page is for anyone whose thyroid biopsy report lists a Bethesda category. It explains what the system is and what to ask.
What the number is reporting
A thyroid fine-needle aspiration (FNA) uses a thin needle to remove thyroid tissue. The National Cancer Institute says several samples may be taken from different parts of the thyroid. A pathologist looks at them under a microscope.
The Bethesda System for Reporting Thyroid Cytopathology sorts results into six diagnostic categories. A category is a report label for one nodule. It is not a diagnosis by itself. Your care team reads it with your ultrasound. An ultrasound can show a nodule's size. It can also show whether the nodule is solid or a fluid-filled cyst.
The National Cancer Institute says thyroid nodules are common and usually are not cancer.
Why two reports can read differently
The system has been updated over time. The 2023 edition was published in the journal literature indexed by the National Library of Medicine. It gave each of the six categories a single name. It also refined the risk of cancer tied to each category. It added pediatric (child) thyroid disease. It aligned the wording with the World Health Organization classification. It also added chapters on molecular (gene-based) testing.
If your report uses older wording, that does not make it wrong. It may mean your lab used an earlier edition. It is fair to ask which edition your lab uses.
Ask for an experienced reader
The National Cancer Institute advises asking to have biopsy samples checked by a pathologist who has experience diagnosing thyroid cancer. Thyroid biopsies can be hard to read, so this is a reasonable request.
If surgery is discussed
The National Cancer Institute describes a lobectomy as removing the lobe of the thyroid in which cancer is found. A total thyroidectomy removes the whole gland. Ask your team why they suggest one or the other.
Questions worth asking about your report
- Which Bethesda category is on my report, and which edition did the lab use?
- What does my care team think this category means for my nodule?
- What did the ultrasound show, and does it agree with the biopsy?
- Should the sample be reviewed by a pathologist with thyroid experience?
- Is more testing, repeat biopsy, or surgery being considered, and why?
Get emergency help or call your care team
Call 911 or go to the nearest emergency room for trouble breathing. Trouble swallowing, pain when swallowing, hoarseness, or a growing neck lump can be signs of a thyroid problem, according to the National Cancer Institute. If you notice any of these, call your care team right away. Do not wait for the follow-up appointment.
Related pages
Thyroid Nodule on Ultrasound: What Now?, What Does TI-RADS Mean?, Thyroid Cancer, and Pathology Reports.
Sources
Common questions
Does a Bethesda category mean I have cancer?
No. It is a report label for one nodule. The National Cancer Institute says thyroid nodules are common and usually are not cancer. Your care team uses the category with your ultrasound and other results.
Why does my report wording differ from what I read online?
The Bethesda system has been updated. The 2023 edition gave each of its six categories a single name. An older report may reflect an earlier edition. It is fair to ask which one your lab used.
Can I ask for a second look at my biopsy?
Yes. The National Cancer Institute advises asking to have biopsy samples checked by a pathologist who has experience diagnosing thyroid cancer.
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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