DEVELOPMENT OF THYROID NODULES

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There are several different medical problems that may lead to the development of Thyroid Nodules. Thyroid nodules may occur singly, or there may be multiple nodules (this has been termed "multinodule goiter").


It is important to evaluate thyroid nodular disease for several reasons. For example, thyroid nodules may indicate an underlying problem with thyroid function, i.e., inadequate or excessive thyroid hormone production.


Without proper treatment, some thyroid nodules continue to grow and actually become a cosmetic problem. One must always consider the possibility of thyroid cancer, since this may show up in a thyroid nodule (often without symptoms). Thyroid cancer, in most cases, is curable if diagnosed early and treated appropriately.





MOST COMMON THYROID NODULES




The most common type if thyroid nodule is called a "Colloid Nodule." Colloid is a protein substance in normal thyroid glands that stores thyroid hormone before it is secreted into the blood stream.


Colloid nodules may be single or multiple and, although the cause is unclear, there is some evidence they develop as a result of minor functional abnormalities which interfere with efficient thyroid hormone production. Patients with colloid nodules usually have normal blood thyroid hormone levels.


The thyroid gland may also develop Adenomas. Adenomas are benign (non-cancerous) tumors. They sometimes become overactive and produce excess amounts of thyroid hormone, leading to Thyrotoxicosis.


Thyroid nodules may also be caused by various forms of thyroiditis (Hashimoto's, subacute and atypical). The thyroid gland may also for simple cysts, which are fluid-filled nodules. Lastly, some nodules represent the development of cancer.





EVALUATION OF THYROID NODULES




The evaluation of thyroid nodules usually starts with a measurement of the blood thyroid hormone level in order to determine how the thyroid gland is functioning. A thyroid antibody test and erythrocyte sedimentation rare may be helpful, since these tests may identify an underlying thyroiditis which is causing thyroid nodule formation.


A measurement of Plasma Thyroglobulin (protein formed in the thyroid gland) may be indicated. Elevated thyroglobulin levels may be seen in certain types of thyroid disease, such a thyroids or cancer, providing diagnostic help in these cases.


Radioisotope scanning is often used to evaluate thyroid nodules. The function of a nodule (whether or not it accumulates isotope), as demonstrated by the thyroid scan, is a very important diagnostic characteristic. Functional nodules which accumulate isotope are almost never cancerous, while hypofunctional nodules which do not accumulate isotope may sometimes harbor carcinoma or cancer.





BIOPSIES OF THYROID NODULES




FINE-NEEDLE BIOPSY




Sometimes tissue samples must be obtained in order to complete the evaluation. Fine-Needle Biopsy is now a very commonly used procedure. This is a simple and safe method of obtaining thyroid tissue for examination under the microscope. A very fine needle is used and there is essentially no risk.


Microscopic samples are obtained from the thyroid tissue and applied to a slide for microscopic examination. All of the evaluation to this point can be done without admitting the patient to the hospital.





SURGICAL BIOPSY




The ultimate test consists of the open Surgical Biopsy. This requires hospitalization and general anesthesia.
Although many thyroid nodules can be managed medically, surgery is sometimes indicated after the initial evaluation, particularly if the presence of a carcinoma has not been definitely excluded. Even if surgery is performed, it is almost always essential that thyroid hormone be administered for the remainder of the patient's life. This prevents regrowth of most thyroid nodules.






SUMMARY


The treatment of thyroid nodular disease may include surgery. Many thyroid nodules, however, can be managed medically. Most often, this consists of taking thyroid hormone by mouth on a daily basis in order to "put the thyroid gland at rest." This is called suppression therapy and, depending on the underlying problem, thyroid nodules may regress in size or, at least, further growth may be prevented. Faithfully taking the thyroid hormone tablet and regular medical followup with the physician are important for the success of thyroid nodule management.










Brought to you by:
Integris Southwest Medical Center Department of Endocrinology 
Jonathan L. Davis, M.D.