The thyroid gland, shaped like a butterfly, sits just below the skin and several thin muscle layers in the lower part of the neck (Fig. 1 Thyroid Anatomy). It’s attached to the deeper neck structures (trachea and voice box) and moves up when we swallow. The thyroid gland secretes hormones that control a variety of systems all through out life including our metabolism, growth and development. Each year about 35,000 Americans are diagnosed with thyroid cancer. It is about 2 to 4 times more common in women than in men, and is most prevalent between ages 25 and 65. All thyroid cancers develop first as a small lump (nodule) in the thyroid gland; however, most nodules are not cancerous. At the CENTER we have a specific protocol for diagnosis and management of thyroid nodules, which is outlined below.
A thyroid nodule is essentially a lump in the thyroid gland (Fig. 2a Thyroid Nodule & 2b Thyroid Nodule). Lumps in the thyroid gland can be very common, and as many as 40-50% of the population can have nodules in their thyroid gland. The problem with thyroid nodules is that both benign and cancerous tumors in the thyroid start as nodules and initially they can have the same appearance, so that they may not be distinguished on ultrasound, CT scan or MRI. Therefore often times when a nodule is found, and if it is large enough, a biopsy is done. If it is too small to biopsy or appears to be not suspicious then it may be monitored by regular examinations or ultrasound. Biopsy of a thyroid nodule is called FNA or Fine Needle Aspiration (Fig. 3 FNA). If the nodule can be felt by touching the neck then we perform the FNA directly; if the nodule is deep and not easily felt, then we perform the FNA under visualization by ultrasound in our office (Fig. 4 Ultrasound Guided FNA). FNA is very simple and will take only a few minutes; numbing medicine is used for more comfort.
Biopsy results are often very clear and helpful, but at times they can be confusing. NCI (National Cancer Institute) has created a classification system that correlates biopsy results with their potential to be cancerous, and abbreviated version is shown in the table below. Once the results are obtained, we advise that you have thorough conversation with your primary physician, endocrinologist and/or surgeon; it is very important to get advice as to what to do next from an experienced physician so that you receive the appropriate treatment. We find that many patients are advised to have surgery when not necessary, and unfortunately a number of patients are told that they don’t need treatment until their cancer grows to be large.
|Table 1. Pathologic Diagnosis on FNA|
|Categories||Diagnostic Terms||Risk of Cancer||Recommendation|
|Benign||» Nodular Goiter» Thyroiditis
» Colloid Nodule
|<1%||» Follow up by clinical exam or ultrasound» Repeat FNA if larger|
|Benign Cystic Lesion||» Simple Cyst» Complex Cyst mixed cystic & solid or >3cm||1-4%14%||» Clinical Correlation & repeat FNA if cyst is complex to rule out cystic papillary cancer|
Cellular Follicular Lesion
|Cases not convincingly benign, yet not sufficiently suspicious to be called neoplasm or suspicious for cancer||5-10%||» Repeat FNA» Correlation with clinical & ultrasound exam|
|NeoplasmSuspicious for Neoplasm||Micro-follicular Proliferation or lesion||20-30%||» Possible Surgery» Hemithyroidectomy|
|Suspicious for Malignancy||Suspicious for Papillary, Medullary, Poorly Differentiated, Anaplastic||50-75%||» Surgery|
|Malignant||Papillary, Medullary, Poorly Differentiated, Anaplastic||100%||» Surgery (Total Thyroidectomy in most Cases)|
|Non-Diagnostic||» Repeat FN|
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