From the Guidelines
The initial evaluation of a thyroid nodule requires TSH measurement, ultrasound, and fine-needle aspiration (FNA) based on sonographic features. First, obtain a serum TSH level to assess thyroid function; suppressed TSH suggests a hyperfunctioning nodule requiring scintigraphy 1. Next, perform a high-resolution thyroid ultrasound to characterize the nodule's size, composition, margins, echogenicity, and presence of calcifications. Nodules with suspicious features (irregular margins, hypoechogenicity, microcalcifications, taller-than-wide shape, or size >1 cm) warrant FNA biopsy. For nodules ≥1 cm with intermediate suspicion or ≥1.5 cm with low suspicion, proceed with FNA 1. Purely cystic nodules rarely require biopsy. If FNA reveals malignancy or suspicious cytology, refer for surgical consultation. For indeterminate cytology, molecular testing helps determine management. Benign nodules need follow-up ultrasound in 6-12 months. Throughout evaluation, assess for compressive symptoms (dysphagia, voice changes, breathing difficulty) and risk factors for thyroid cancer (radiation exposure, family history) 1.
Some key points to consider in the evaluation process include:
- The incidence of thyroid cancer has been increasing, but mortality has been slowly decreasing due to improved diagnostic accuracy 1.
- Fine needle aspiration cytology (FNAC) is a sensitive tool for differentiating between benign and malignant nodules, but has limitations such as inadequate samples and follicular neoplasia 1.
- Measurement of serum calcitonin is a reliable tool for diagnosing medullary thyroid cancer and should be an integral part of the diagnostic evaluation of thyroid nodules 1.
- The initial treatment of differentiated thyroid carcinoma (DTC) should always be preceded by careful exploration of the neck by ultrasound to assess the status of lymph node chains 1.
The most important step is to prioritize the evaluation based on sonographic features and TSH levels, and then proceed with FNA and other diagnostic tests as needed. This systematic approach efficiently identifies nodules requiring intervention while avoiding unnecessary procedures for benign lesions.
From the Research
Initial Evaluation
The initial evaluation of a patient presenting with a thyroid nodule typically includes:
- Measurement of serum TSH to assess thyroid function 2, 3
- Ultrasonographic characteristics to guide the initial management of thyroid nodules 4, 2
- Fine needle aspiration biopsy (FNA) for cytological evaluation, especially for nodules with suspicious sonographic patterns 5, 4, 6
Management Approach
The management approach for a patient presenting with a thyroid nodule depends on the initial risk estimate, derived from ultrasound and cytology report, and includes:
- Simple observation for benign nodules 4, 2
- Local treatments, such as radioactive iodine, for selected cases 2
- Surgery for nodules with malignant cytology or compressive symptoms 4, 2
- Molecular testing for indeterminate cytology 4
Key Components of Evaluation
The key components of a thyroid nodule evaluation include:
- TSH value, which is vital to any thyroid nodule evaluation 3
- High-quality ultrasound with commentary on nodule size, structure, echogenicity, and lymph nodes 3
- Fine needle aspiration biopsy for cytological evaluation 5, 4, 6
Variation in Evaluation Quality
There is great variation in the quality of thyroid nodule evaluations before surgical referral, with many evaluations lacking a TSH value or a high-quality ultrasound 3