A focal area of increased uptake is called a hot nodule. These hot nodules virtually never represent malignant disease but instead usually represent either autonomous or hypertrophic adenomas. Thyroid function tests and suppression scans can play a role in working up these hot lesions. Occasionally, a simple cyst can be found and in this situation no further work-up is usually required. However, simple cysts are rare and any nodule found usually requires more investigation.
Some clinicians use ultrasound to guide biopsies or to follow the size of nodules.
Numerous studies since the 1970 s have shown the usefulness of this procedure. As might be expected, experience plays a critical role in attaining the highest sensitivities and specificities. Problems with FNA include difficulty differentiating follicular adenoma from carcinoma, false positives in Hashimoto s thyroiditis, and false negatives due to inadequate sampling. The work-up of thyroid nodules remains somewhat controversial. A good history, physical exam, and thyroid function tests often provide valuable clues in reaching a correct diagnosis but are non-specific.