Thyroid Nodules in Primary Care: What to Do Next

A patient feels a lump in their neck, or a nodule turns up on a scan you ordered for something else. Most are benign, but you still need a clear path so nothing falls through the cracks.

Here's the workup, simplified for a busy clinic.

Who gets nodules, and why it matters

• Adults: most nodules are benign. Multinodular goiter, colloid nodules, and cysts are common.
• Children: nodules are less common but more likely to be malignant, so refer early to endocrine or surgery.
• Concerning features: a fixed, firm, non-tender nodule, rapid growth, hoarseness, dysphagia or dyspnea, cervical lymphadenopathy, prior head or neck radiation, or a strong family history of thyroid cancer.

One thing to keep straight: hyper or hypothyroid symptoms don't rule cancer in or out. Most nodules occur with normal thyroid function.

What's the day-one workup?

Two steps cover most patients:

1. Check a TSH.
   • Low TSH: consider a radionuclide uptake scan. A hyperfunctioning "hot" nodule is rarely malignant, and FNA usually isn't indicated.
   • Normal or high TSH: move to ultrasound risk stratification.
2. Get a dedicated thyroid ultrasound. Ask radiology to apply TI-RADS (ACR) or ATA pattern-based risk stratification and to document:
   • Composition (solid, cystic, mixed)
   • Echogenicity (hypoechoic, isoechoic, and so on)
   • Margins (smooth vs irregular)
   • Taller-than-wide shape
   • Microcalcifications
   • Size in three dimensions
   • Cervical lymph nodes

The features that raise suspicion: solid and hypoechoic, irregular or lobulated margins, microcalcifications, taller-than-wide, extrathyroidal extension, and suspicious nodes. If you want the broader lab context, see how to read thyroid labs fast.

When do I biopsy (FNA)?

Thresholds vary by system, so follow your local radiology, ATA, or ACR guidance. A simple ATA-style snapshot:

• High-suspicion pattern: FNA at 1.0 cm or larger
• Intermediate-suspicion: FNA at 1.0 cm or larger
• Low-suspicion: FNA at 1.5 cm or larger
• Very-low suspicion or spongiform: consider FNA at 2.0 cm or larger, or observe
• Purely cystic: no FNA

If TSH is low and the uptake scan shows a hot nodule, FNA usually isn't needed.

How do I manage and follow up?

• Benign cytology (Bethesda II): annual TSH and a targeted neck exam, with ultrasound at about 12 to 24 months, then extend the interval if it's stable. Re-biopsy for growth (more than 20% increase in 2 or more dimensions with a minimum increase of 2 mm, or more than a 50% volume increase) or new suspicious features.
• Indeterminate cytology (Bethesda III/IV): discuss molecular testing and/or endocrine or surgical referral.
• Suspicious or malignant cytology (Bethesda V/VI): refer to endocrine and surgery for definitive management.
• Compressive symptoms (dysphagia, dyspnea, voice change) or cosmetic concerns with a benign nodule: refer to endocrine and surgery. They'll weigh surgical options or nonsurgical ones like ethanol or radiofrequency ablation, depending on local availability.

A few special notes

• Biotin can distort thyroid labs (falsely low TSH, high T4/T3). Have patients hold it for 48 hours before testing.
• Pregnancy: avoid radionuclide scanning and coordinate with endocrinology.
• Children and adolescents: lower biopsy threshold and early specialty referral.

A quick way to counsel the patient

Something like: "Most nodules are benign. We'll check your hormone levels and get a high-quality ultrasound. If the ultrasound meets certain criteria, we'll do a small needle biopsy. If the biopsy is benign, we'll monitor it over time."

And the safety net: "Call urgently for voice changes, trouble swallowing or breathing, or rapid growth."

Frequently asked questions

Does a nodule mean cancer?
Usually not. Most adult nodules are benign. The workup is about catching the small percentage that aren't.

Do all nodules need a biopsy?
No. Whether to biopsy depends on the ultrasound risk pattern and the size. Purely cystic and hot nodules generally don't need FNA.

What if the TSH is low?
Consider an uptake scan. A hot nodule is rarely malignant, so FNA usually isn't needed.

How often do I image a benign nodule?
Ultrasound at about 12 to 24 months, then extend the interval if it's stable. Re-biopsy only for significant growth or new suspicious features.

For the labs behind a low or high TSH, see how to read thyroid labs fast. Want this on one page at your desk? The Clinical Desk Reference is a $37 quick-reference. For the full system on working through any visit, the Primary Care Clinical Mastery Program is AANP-accredited.

Education only. Use your clinical judgment and local protocols.

Written by Allison Sowders, MSN, APRN, FNP-BC, a practicing primary care nurse practitioner and founder of Nurse Practitioner Mentor. Reviewed July 2026.