# Thyroid Nodule Evaluation

> NEET-PG surgery notes on thyroid nodule evaluation covering ultrasound, FNAC, cancer risk factors and management with exam points.

- Canonical URL: https://prepelephant.com/topics/neet-pg/surgery/thyroid-nodule-evaluation
- Exam / course: NEET-PG · Subject: Surgery
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Thyroid Nodule Evaluation", PrepElephant, https://prepelephant.com/topics/neet-pg/surgery/thyroid-nodule-evaluation

## Direct answer

A thyroid nodule is a discrete swelling within the gland, and the clinical task is to exclude malignancy, which is present in only a small minority. Evaluation starts with a TSH and high-resolution ultrasound; a nodule with a suppressed TSH is assessed by radionuclide scan, because a hyperfunctioning "hot" nodule is rarely malignant. Fine-needle aspiration cytology, reported on the Bethesda system, is the diagnostic mainstay for sonographically suspicious nodules.

## What you must remember

- Suspicious clinical features — hard fixed nodule, rapid growth, hoarseness from recurrent laryngeal nerve palsy, cervical lymphadenopathy, extremes of age, male sex and previous neck irradiation.
- Suspicious ultrasound features — microcalcifications, marked hypoechogenicity, irregular margins, taller-than-wide shape, extrathyroidal extension and abnormal nodes; risk is stratified using TI-RADS-type systems.
- FNAC is the investigation of choice for a solid nodule with normal or raised TSH; Bethesda categories run from non-diagnostic to suspicious for malignancy and guide repeat aspiration, surveillance or surgery.
- A hot (autonomous) nodule with suppressed TSH is confirmed on radioiodine or technetium scan and is very rarely cancer; options include observation, antithyroid drugs, radioiodine or surgery.
- Papillary carcinoma is the commonest thyroid malignancy — lymphatic spread, Orphan-Annie eye nuclei, nuclear grooves and psammoma bodies — with an excellent prognosis.
- Follicular carcinoma spreads haematogenously and needs histology for vascular and capsular invasion; medullary carcinoma arises from C cells, secretes calcitonin, links to MEN 2 and RET mutations; anaplastic carcinoma afflicts the elderly with dismal outcomes.
- Before any thyroid surgery, check vocal cord movement; after total thyroidectomy, monitor calcium.

## Common confusion

Hot and cold nodules are perpetually confused. A cold nodule simply takes up less isotope and, while most are benign, virtually all thyroid cancers appear cold — so cold raises suspicion. A hot nodule with a suppressed TSH autonomously produces hormone and is almost never malignant, which is why scintigraphy is used only when TSH is low. Also, a nodule within a multinodular goitre carries broadly similar malignancy risk to a solitary nodule, so "dominant nodule in a goitre" still needs evaluation.

## Exam-focused takeaway

Expect a sequence question — TSH and ultrasound first, FNAC for suspicious solid nodules, scintigraphy when TSH is suppressed. Histology buzzwords (Orphan-Annie nuclei, psammoma bodies, amyloid stroma with calcitonin staining) appear in slide-based questions. Hoarseness with a hard fixed nodule is the red-flag vignette pointing straight to carcinoma and surgery.

## Frequently asked questions

### What is the first-line evaluation of a thyroid nodule?

Serum TSH plus high-resolution ultrasound. The TSH result and ultrasound pattern then decide whether FNAC, scintigraphy or surveillance follows.

### When is a radionuclide scan used?

When TSH is suppressed, to confirm a hyperfunctioning hot nodule, which is very rarely malignant. Cold nodules cannot be distinguished from benign lesions on scan alone.

### What does the Bethesda system do?

It standardises FNAC reporting into diagnostic categories, each with a malignancy risk and recommended action — from repeat sampling for non-diagnostic lesions to surgery for suspicious or malignant cytology.

### Which tumour marker is followed in medullary carcinoma?

Calcitonin, often with carcinoembryonic antigen. Medullary carcinoma is associated with MEN 2 syndromes and RET proto-oncogene mutations, demanding family screening.

### Why is hoarseness significant with a nodule?

It suggests recurrent laryngeal nerve involvement by an infiltrating carcinoma. Cord movement should be checked before thyroidectomy in every patient.