Even though they grow slowly, papillary cancers often spread to the lymph nodes in the neck. Even when these cancers have spread to the lymph nodes, they can often be treated successfully and are rarely fatal. There are several subtypes of papillary cancers. Of these, the follicular subtype also called mixed papillary-follicular variant is most common.
It has the same good outlook prognosis as the standard type of papillary cancer when found early, and they are treated the same way. Other subtypes of papillary carcinoma columnar, tall cell, insular, and diffuse sclerosing are not as common and tend to grow and spread more quickly.
Follicular cancer also called follicular carcinoma or follicular adenocarcinoma : Follicular cancer is the next most common type, making up about 1 out of 10 thyroid cancers. These cancers usually do not spread to lymph nodes, but they can spread to other parts of the body, such as the lungs or bones.
The outlook prognosis for follicular cancer is not quite as good as that of papillary cancer, although it is still very good in most cases. It is harder to find and to treat. It develops from the C cells of the thyroid gland, which normally make calcitonin, a hormone that helps control the amount of calcium in blood. Sometimes this cancer can spread to lymph nodes, the lungs, or liver even before a thyroid nodule is discovered.
It is thought to sometimes develop from an existing papillary or follicular cancer. This cancer is called undifferentiated because the cancer cells do not look very much like normal thyroid cells.
This cancer often spreads quickly into the neck and to other parts of the body, and is very hard to treat. Behind, but attached to, the thyroid gland are 4 tiny glands called the parathyroids. Cancers of the parathyroid glands are very rare — there are probably fewer than cases each year in the United States. It weighs less than an ounce, but helps the body do many important things, such as grow, regulate energy, and go through sexual development.
An enlarged thyroid gland can be felt as a lump under the skin at the front of the neck. When it is large enough to see easily, it's called a goiter. A thyroid nodule is a lump or enlarged area in the thyroid gland. A nodule may simply be swollen tissue, an overgrowth of normal thyroid tissue, or a collection of fluid called a cyst.
Most thyroid nodules in children are not caused by cancer. Goiters can happen due to inflammation of the thyroid gland or when the gland makes too much or too little thyroid hormone. A goiter also can develop with other thyroid problems, such as infections of the thyroid or thyroid cysts, tumors, or thyroid cancer. People who don't get enough iodine in their diets also can get an enlarged thyroid. But this is rare in the United States because foods here usually supply enough iodine.
Kids can be born with a goiter or develop one later in life. A goiter that's present at birth is called a congenital goiter. These can be caused by:. A goiter that develops later is called an acquired goiter. In the United States, most acquired goiters are caused by:. Hashimoto's thyroiditis : The immune system attacks the thyroid, making it swell. Sometimes this swelling can be dramatic and even look like a growth.
Over time, the thyroid can become so damaged that it can't make enough thyroid hormone. In that case, a person might need to take a thyroid hormone. Graves' disease : This is the most common cause of a goiter with high thyroid hormone levels in kids, and the top cause of hyperthyroidism in teen girls.
The immune system attacks parts of the thyroid gland, making it swell and produce too much thyroid hormone. It also can cause inflammation and swelling around the eyes. Colloid goiter also called the "adolescent goiter" : The thyroid sometimes grows a lot during puberty , and can look abnormally large.
This is not associated with any thyroid hormone problems. The thyroid works normally and often gets smaller over time with no treatment. Viral or bacterial infections: Infections can cause inflammation and enlargement of the thyroid. These goiters are often painful. The most common cause of a thyroid nodule in kids is actually a "pseudonodule" or "fake nodule. This inflammation might look like a nodule, but there isn't really any nodule at all.
The thyroid gland is normally about the size of two thumbs held together in the shape of a V. It can enlarge when it is inefficient in making thyroid hormones, inflamed, or occupied by tumors. Thyroid gland enlargement can be generalized and smooth, a so called diffuse goiter ; or it can become larger due to growth of one or more discrete lumps nodules within the gland, a nodular goiter.
A goitrous gland can continue producing the proper amounts of thyroid hormones, in which case it is called a euthyroid or nontoxic goiter ; or a goiter can develop in conditions with either overproduction of thyroid hormone, called toxic goiter , or the inability to make sufficient thyroid hormones, called goitrous hypothyroidism. A thyroid nodule is simply a lump or mass in the thyroid gland. Moreover, close inspection of the thyroid by sonographic imaging shows that as many as one-third of women and one-fifth of men have small nodules in their glands.
The thyroid may contain just one nodule solitary thyroid nodule or uninodular goiter or several of them multinodular goiter. Thyroid nodules can be solid if they are comprised of thyroid or other cells or an accumulation of stored thyroid hormone called colloid.
When nodules contain fluid, they are called cystic nodules. These can be completely fluid filled simple cysts , or partly solid and partly fluid, complex cysts. Thyroid nodules vary greatly in size. Many are large enough to see and feel palpable nodules. Some multinodular goiters can become enormous, bulging out of the neck and over the collar bones or extending down into the chest behind the breastbone, a condition called substernal goiter. At the other end of the spectrum, the majority of thyroid nodules are too small to see or feel at all, and are called nonpalpable nodules.
Such small nodules are found when a person has a medical imaging procedure performed for some other reason, such as a sonogram of the carotid arteries; a CAT or MRI scan of their neck, head, or chest; or a PET scan. These very small, incidentally detected thyroid nodules are called thyroid incidentalomas.
Finally, of course, thyroid nodules can also be classified as benign or malignant depending on whether the cells of which they are comprised have the potential to spread beyond the thyroid gland into adjacent tissues or distant parts of the body. Specific causes of thyroid nodules and how they are distinguished are discussed below.
A multi-nodular goiter is an enlarged thyroid gland with a goiter comprised of multiple thyroid nodules. The nodules can be very small often only a few millimeters in size or a larger size several centimeters and there is often a dominant nodule.
The key question is whether the nodules are benign or malignant cancerous. This is discussed in more detail below. To understand why some types of goiter develop, it is first important to know what the normal function of the thyroid gland is and how it is regulated. The thyroid gland makes and releases into blood two small chemicals, called thyroid hormones: thyroxine T4 and triiodothyronine T3.
Each of them is comprised of a pair of connected tyrosine amino acids to which four or three iodine molecules, respectively, are attached. The iodine needed for thyroid hormone production comes from our diet in seafood, dairy products, store bought bread, and iodized salt.
Once absorbed, iodine in blood is trapped by a special pump in thyroid cells, called the sodium-iodide symporter. The thyroid also has several specialized biochemical 'fastening machines,' called enzymes, that then carry out the steps needed to attach iodine to particular parts of a very big protein called thyroglobulin, which is made only by thyroid cells.
Some of this thyroglobulin with iodine molecules attached is stored in the gland in the form of a gooey paste called colloid , which is normally located in the center of follicles, which are balls of thyroid cells with a hollow center. A regulated amount of the thyroid hormones is constantly being chopped off of thyroglobulin and secreted into blood for delivery to tissues throughout the body. In the nucleus of almost every cell, thyroid hormones bind to molecules called T3 receptors, which are attached to segments of DNA that regulate certain genes.
Precise control of how many proteins are made from these genetic blueprints maintains the normal or euthyroid thyroid state. Excessive activation of these genes by abnormally high thyroid hormone levels causes hyperthyroidism; inadequate gene activation due to insufficient thyroid hormone production causes hypothyroidism.
The thyroid normally makes precisely the right amount of its hormones under the exacting control of the pituitary gland, which is an extension of the brain. Specialized pituitary cells make thyroid stimulating hormone TSH , which travels in blood to the thyroid gland, where TSH binds to its own receptors on thyroid cells, prompting them to grow and produce more of the thyroid hormones.
Normally, this system is kept in balance by the negative feedback of the thyroid hormones on TSH-secreting pituitary cells as well as the part of the brain that controls them.
Three categories of problems are responsible for almost all cases of thyroid gland enlargement: inefficient thyroid hormone production, gland inflammation, and tumors in the thyroid:. Painful, tender and swollen gland Malaise, fever, chills, and night sweats Thyrotoxicosis, often followed by hypothyroidism. Thyroid nodules, masses in the thyroid gland, can be the result of benign cell overgrowth adenomatous hyperplasia or actual discrete tumors comprised of thyroid cells that can be benign or cancerous.
Thyroid nodules can sometimes contain fluid, which usually collects due to bleeding from the fragile blood vessels in thyroid tumors, so called cystic degeneration. This event sometimes causes the sudden onset of pain and swelling in the front of the neck, which typically subsides over several days. Often patients with small thyroid nodules, less than 1 cm in diameter, and no risk factors for thyroid cancer can simply be reexamined or imaged by sonography to be sure the nodule is not enlarging.
For larger nodules, additional studies are usually indicated, as described below. Whenever a person has a goiter or thyroid nodule, three questions must be answered. Answering these three important questions begins with collecting certain facts about the person's medical history and any recent symptoms.
Table 2. Goiter and nodules are more common in women and older people, but nodules in men and younger are somewhat more likely to be cancer.
Swelling or pain in the front of the neck Hoarseness that is new and persistent Cough that is new and persistent Coughing up blood Shortness of breath. Weight loss, heat intolerance, trembling hands, palpitations, insomnia, anxiety, increased bowel movement frequency - especially if the symptoms are new or persistent.
Weight gain, cold intolerance, constipation, very dry skin, slowed thinking, depressed mood, muscle cramps - especially if the symptoms are new or persistent. Childhood neck radiation Family history of thyroid cancer Family history of colon polyps Family history of parathyroid or adrenal tumors. A doctor will look on physical examination for signs related to the thyroid enlargement: the entire gland or nodule size; its firmness, mobility, and tenderness; and whether there is any nearby lymph node enlargement.
The doctor will also look for signs of thyroid hormone excess or deficiency. Although the history and physical examination sometimes provide important clues, it is almost always necessary to perform additional diagnostic tests to answer the key clinical questions with certainty.
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