Thyroid neoplasm

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Thyroid neoplasm
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Thyroid neoplasm is a neoplasm or tumor of the thyroid. It can be a benign tumor such as thyroid adenoma, [1] or it can be a malignant neoplasm (thyroid cancer), such as papillary, follicular, medullary or anaplastic thyroid cancer. [2] Most patients are 25 to 65 years of age when first diagnosed; women are more affected than men. [2] [3] The estimated number of new cases of thyroid cancer in the United States in 2010 is 44,670 compared to only 1,690 deaths. [4] Of all thyroid nodules discovered, only about 5 percent are cancerous, and under 3 percent of those result in fatalities.

Contents

Diagnosis

The first step in diagnosing a thyroid neoplasm is a physical exam of the neck area. If any abnormalities exist, a doctor needs to be consulted. A family doctor may conduct blood tests, an ultrasound, and nuclear scan as steps to a diagnosis. The results from these tests are then read by an endocrinologist who will determine what problems the thyroid has. Hyperthyroidism and hypothyroidism are two conditions that often arise from an abnormally functioning thyroid gland. These occur when the thyroid is producing too much or too little thyroid hormone respectively. [4]

Thyroid nodules are a major presentation of thyroid neoplasms, and are diagnosed by ultrasound guided fine needle aspiration (USG/FNA) or frequently by thyroidectomy (surgical removal and subsequent histological examination). FNA is the most cost-effective and accurate method of obtaining a biopsy sample. [5] As thyroid cancer can take up iodine, radioactive iodine is commonly used to treat thyroid carcinomas, followed by TSH suppression by high-dose thyroxine therapy.[ citation needed ]

Nodules are of particular concern when they are found in those under the age of 20. The presentation of benign nodules at this age is less likely, and thus the potential for malignancy is far greater.[ citation needed ]

Classification

Thyroid neoplasm might be classified as benign or malignant.[ citation needed ]

Benign neoplasms

Thyroid adenoma is a benign neoplasm of the thyroid. Thyroid nodules are very common and around 80 percent of adults will have at least one by the time they reach 70 years of age. Approximately 90 to 95 percent of all nodules are found to be benign. [4]

Malignant neoplasms

Thyroid cancers are mainly papillary, follicular, medullary or anaplastic thyroid cancer. [2] Most patients are 25 to 65 years of age when first diagnosed; women are more affected than men. [2] [3] Nearly 80 percent of thyroid cancer is papillary and about 15 percent is follicular; both types grow slowly and can be cured if caught early. Medullary thyroid cancer makes up about 3 percent of this cancer. It grows slowly and can be controlled if caught early. Anaplastic is the most deadly and makes up around 2 percent. This type grows quickly and is hard to control. [4] The classification is determined by looking at the sample of cells under a microscope and determining the type of thyroid cell that is present. Other thyroid malignancies include thyroid lymphoma, various types of thyroid sarcoma, smooth muscle tumors, teratoma, squamous cell thyroid carcinoma and other rare types of tumors. [6]

Treatment

Treatment of a thyroid nodule depends on many things including size of the nodule, age of the patient, the type of thyroid cancer, and whether or not it has spread to other tissues in the body. If the nodule is benign, patients may receive thyroxine therapy to suppress thyroid-stimulating hormone and should be reevaluated in 6 months. [2] However, if the benign nodule is inhibiting the patient's normal functions of life; such as breathing, speaking, or swallowing, the thyroid may need to be removed.[ citation needed ]Sometimes only part of the thyroid is removed in an attempt to avoid causing hypothyroidism. There's still a risk of hypothyroidism though, as the remaining thyroid tissue may not be able to produce enough hormones in the long-run.

If the nodule is malignant or has indeterminate cytologic features, it may require surgery. [2] A thyroidectomy is a medium-risk surgery that can result in complications if not performed correctly. Problems with the voice, nerve or muscular damage, or bleeding from a lacerated blood vessel are rare but serious complications that may occur. After removing the thyroid, the patient must be supplied with a replacement hormone for the rest of their life. This is commonly a daily oral medication prescribed by their endocrinologist.[ citation needed ]

Radioactive iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy. [2] External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis. [2]

See also

Related Research Articles

Thyroid Endocrine gland in the neck; secretes hormones that influence metabolism

The thyroid, or thyroid gland, is an endocrine gland in the neck consisting of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thyroid is located at the front of the neck, below the Adam's apple. Microscopically, the functional unit of the thyroid gland is the spherical thyroid follicle, lined with follicular cells (thyrocytes), and occasional parafollicular cells that surround a lumen containing colloid. The thyroid gland secretes three hormones: the two thyroid hormones – triiodothyronine (T3) and thyroxine (T4) – and a peptide hormone, calcitonin. The thyroid hormones influence the metabolic rate and protein synthesis, and in children, growth and development. Calcitonin plays a role in calcium homeostasis. Secretion of the two thyroid hormones is regulated by thyroid-stimulating hormone (TSH), which is secreted from the anterior pituitary gland. TSH is regulated by thyrotropin-releasing hormone (TRH), which is produced by the hypothalamus.

Thyroidectomy total or partial removal of the thyroid gland

A thyroidectomy is an operation that involves the surgical removal of all or part of the thyroid gland. General, endocrine or head and neck surgeons often perform a thyroidectomy when a patient has thyroid cancer or some other condition of the thyroid gland or goiter. Other indications for surgery include cosmetic, or symptomatic obstruction. Thyroidectomy is a common surgical procedure that has several potential complications or sequelae including: temporary or permanent change in voice, temporary or permanently low calcium, need for lifelong thyroid hormone replacement, bleeding, infection, and the remote possibility of airway obstruction due to bilateral vocal cord paralysis. Complications are uncommon when the procedure is performed by an experienced surgeon.

Thyroglobulin mammalian protein found in Homo sapiens

Thyroglobulin (Tg) is a 660 kDa, dimeric glycoprotein produced by the follicular cells of the thyroid and used entirely within the thyroid gland. Tg is secreted and accumulated at hundreds of grams per litre in the extracellular compartment of the thyroid follicles, accounting for approximately half of the protein content of the thyroid gland. Human TG (hTG) is a homodimer of subunits each containing 2768 amino acids as synthesized.

Adenoma Type of benign tumor

An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others. Some adenomas grow from epithelial tissue in nonglandular areas but express glandular tissue structure. Although adenomas are benign, they should be treated as pre-cancerous. Over time adenomas may transform to become malignant, at which point they are called adenocarcinomas. Most adenomas do not transform. However, even though benign, they have the potential to cause serious health complications by compressing other structures and by producing large amounts of hormones in an unregulated, non-feedback-dependent manner. Some adenomas are too small to be seen macroscopically but can still cause clinical symptoms.

This is a list of terms related to oncology. The original source for this list was the US National Cancer Institute's public domain Dictionary of Cancer Terms.

The International Classification of Diseases for Oncology (ICD-O) is a domain-specific extension of the International Statistical Classification of Diseases and Related Health Problems for tumor diseases. This classification is widely used by cancer registries.

Thyroid disease type of endocrine disease

Thyroid disease is a medical condition that affects the function of the thyroid gland. The thyroid gland is located at the front of the neck and produces thyroid hormones that travel through the blood to help regulate many other organs, meaning that it is an endocrine organ. These hormones normally act in the body to regulate energy use, infant development, and childhood development.

Hürthle cell Thyroid follicles lined by deeply eosinophilic Hürthle cells are seen in Hashimoto disease

A Hürthle cell is a cell in the thyroid that is often associated with Hashimoto's thyroiditis as well as benign and malignant tumors. This version is a relatively rare form of differentiated thyroid cancer, accounting for only 3-10% of all differentiated thyroid cancers. Oncocytes in the thyroid are often called Hürthle cells. Although the terms oncocyte, oxyphilic cell, and Hürthle cell are used interchangeably, Hürthle cell is used only to indicate cells of thyroid follicular origin.

Hürthle cell adenoma is a rare benign tumor, typically seen in women between the ages of 70 and 80 years old. This adenoma is characterized by a mass of benign Hürthle cells. Typically such a mass is removed because it is not easy to predict whether it will transform into the malignant counterpart, a subtype of follicular thyroid cancer called a Hürthle cell carcinoma.

Anaplastic thyroid cancer form of thyroid cancer

Anaplastic thyroid cancer (ATC), also known as anaplastic thyroid carcinoma, is an aggressive form of thyroid cancer characterized by uncontrolled growth of cells in the thyroid gland. This form of cancer generally carries a very poor prognosis due to its aggressive behavior and resistance to cancer treatments. The cells of anaplastic thyroid cancer are highly abnormal and usually no longer resemble the original thyroid cells and have poor differentiation.

Papillary thyroid cancer thyroid carcinoma that is characterized by the small mushroom shape of the tumor which has a stem attached to the epithelial layer

Papillary thyroid cancer or papillary thyroid carcinoma is the most common type of thyroid cancer, representing 75 percent to 85 percent of all thyroid cancer cases. It occurs more frequently in women and presents in the 20–55 year age group. It is also the predominant cancer type in children with thyroid cancer, and in patients with thyroid cancer who have had previous radiation to the head and neck. It is often well-differentiated, slow-growing, and localized, although it can metastasize.

Thyroid adenoma Human disease

A thyroid adenoma is a benign tumor of the thyroid gland, that may be inactive or active as a toxic adenoma.

Thyroid nodule human disease

Thyroid nodules are nodules which commonly arise within an otherwise normal thyroid gland. They may be hyperplastic or tumorous, but only a small percentage of thyroid tumors are malignant. Small, asymptomatic nodules are common, and often go unnoticed. Nodules that grow larger or produce symptoms may eventually need medical care. A goitre may have one nodule – uninodular, multiple nodules – multinodular, or be diffuse.

Follicular thyroid cancer thyroid carcinoma that has material basis in follicular cells

Follicular thyroid cancer accounts for 15% of thyroid cancer and occurs more commonly in women over 50 years of age. Thyroglobulin (Tg) can be used as a tumor marker for well-differentiated follicular thyroid cancer. Thyroid follicular cells are the thyroid cells responsible for the production and secretion of thyroid hormones.

Medullary thyroid cancer malignant thyroid neoplasm originating from C-cells

Medullary thyroid cancer is a form of thyroid carcinoma which originates from the parafollicular cells, which produce the hormone calcitonin. Medullary tumors are the third most common of all thyroid cancers and together make up about 3% of all thyroid cancer cases. MTC was first characterized in 1959.

Multiple endocrine neoplasia type 2B autosomal dominant disease characterized by medullary thyroid carcinoma, pheochromocytoma, multiple mucosal neuromas and intestinal ganglioneuromas, and often a marfanoid habitus and other skeletal abnormalities

Multiple endocrine neoplasia type 2B is a genetic disease that causes multiple tumors on the mouth, eyes, and endocrine glands. It is the most severe type of multiple endocrine neoplasia, differentiated by the presence of benign oral and submucosal tumors in addition to endocrine malignancies. It was first described by Wagenmann in 1922, and was first recognized as a syndrome in 1965-1966 by E.D. Williams and D.J. Pollock.

Thyroid cancer endocrine gland cancer located in the thryoid gland located in the neck below the thyroid cartilage

Thyroid cancer is cancer that develops from the tissues of the thyroid gland. It is a disease in which cells grow abnormally and have the potential to spread to other parts of the body. Symptoms can include swelling or a lump in the neck. Cancer can also occur in the thyroid after spread from other locations, in which case it is not classified as thyroid cancer.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an indolent thyroid tumor that was previously classified as an encapsulated follicular variant of papillary thyroid carcinoma, necessitating a new classification as it was recognized that encapsulated tumors without invasion have an indolent behavior, and may be over-treated if classified as a type of cancer.

In CT scan of the thyroid, focal and diffuse thyroid abnormalities are commonly encountered. These findings can often lead to a diagnostic dilemma, as the CT reflects the nonspecific appearances. Ultrasound (US) examination has a superior spatial resolution and is considered the modality of choice for thyroid evaluation. Nevertheless, CT detects incidental thyroid nodules (ITNs) and plays an important role in the evaluation of thyroid cancer.

Dr. Yuri Nikiforov is an American scientist who revolutionized the understanding of thyroid cancer, most recently winning a two-year battle in which the World Health Organization has agreed in 2017 to reclassify non-invasive thyroid tumors to non-cancerogenic liaisons. Those tumors typically have some, but not all, characteristics of cancer. The WHO has agreed to change the term for the tumors from Encapsulated Follicular Variant of Papillary Thyroid Carcinoma to Noninvasive Follicular Thyroid Neoplasm With Papillary-like Nuclear Features, or NIFTP. About 45,000 people a year are diagnosed with NIFTP in the world. The decision led to a change in protocol of medical treatment, which no longer required removal of the whole thyroid gland from such patients as well as ended the use of radioactive iodine, extending their life expectancy and quality of life. The patients still undergo surgery, in which their thyroid tumors are removed, typically with half, but not all, of the thyroid gland.

References

  1. Chapter 20 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology. Philadelphia: Saunders. ISBN   978-1-4160-2973-1. 8th edition.
  2. 1 2 3 4 5 6 7 8 Hu MI, Vassilopoulou-Sellin R, Lustig R, Lamont JP. "Thyroid and Parathyroid Cancers" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) Cancer Management: A Multidisciplinary Approach. 11 ed. 2008.
  3. 1 2 Al-Zaher N, Al-Salam S, El Teraifi H. Thyroid carcinoma in the United Arab Emirates: perspectives and experience of a tertiary care hospital. Hematol Oncol Stem Cell Ther 2008;1:14-21. "Hematology/Oncology and Stem Cell Therapy"
  4. 1 2 3 4 National Cancer Institute. What You Need to Know About Thyroid Cancer National Cancer Institute, 2010.Print
  5. Schmitt, Fernando. "Thyroid Cytology: Is FNA Still The Best Diagnostic Approach?"International Journal of Surgical Pathology, June 2010, vol 18, p.201-204.
  6. DeLellis R.A.; Lloyd R.V.; Heitz P.U.; et al., eds. (2004). World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Endocrine Organs. Lyon, France: IARC Press. pp. 94–123. ISBN   978-92-832-2416-7.
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