Follicular thyroid cancer | |
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Other names | Follicular thyroid carcinoma |
Micrograph of follicular thyroid carcinoma showing a location where the cancer grows through the fibrous capsule. H&E stain. | |
Specialty | ENT surgery, oncology |
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.
Approximately one-half of follicular thyroid carcinomas have mutations in the Ras subfamily of oncogenes, most notably HRAS, NRAS, and KRAS. [1] Mutations in MINPP1 have likewise been observed, as well as germline PTEN gene mutations responsible for Cowden syndrome of which follicular thyroid cancer is a feature. Also, a chromosomal translocation specific for follicular thyroid carcinomas is one between paired box gene 8 (PAX-8), a gene important in thyroid development, and the gene encoding peroxisome proliferator-activated receptor γ 1 (PPARγ1), a nuclear hormone receptor contributing to terminal differentiation of cells. The PAX8-PPARγ1 fusion is present in approximately one-third of follicular thyroid carcinomas, specifically those cancers with a t(2;3)(q13;p25) translocation, permitting juxtaposition of portions of both genes. [1] This subtype may potentially be treated with pioglitazone, a thiazolidinedione-class drug that potentiates PPARγ to boost insulin sensitivity. [2] Tumors tend to carry either a RAS mutation or a PAX8-PPARγ1 fusion, and only rarely are both genetic abnormalities present in the same case. [1] Thus, follicular thyroid carcinomas seem to arise by two distinct and virtually nonoverlapping molecular pathways. [1]
Hurthle cell thyroid cancer is often considered a variant of follicular cell carcinoma. [3] [4] Hurthle cell forms are more likely than follicular carcinomas to be bilateral and multifocal and to metastasize to lymph nodes. Like follicular carcinoma, unilateral hemithyroidectomy is performed for non-invasive disease, and total thyroidectomy for invasive disease.
It is difficult to correctly diagnose follicular neoplasms (FNs) on fine-needle aspiration cytology (FNAC) because it shares many cytological features with other mimicking lesions. [5]
It is impossible to distinguish between follicular adenoma and carcinoma on cytological grounds. If fine needle aspiration cytology (FNAC) suggests follicular neoplasm, thyroid lobectomy should be performed to establish the histopathological diagnosis. Features sine qua non for the diagnosis of follicular carcinoma are capsular invasion and vascular invasion by tumor cells. Still, focuses of the capsular invasion should be carefully evaluated and discriminated from the capsular rupture due to FNA penetration resulting in WHAFFT (worrisome histologic alterations following FNA of thyroid).
HMGA2 has been proposed as a marker to identify malignant tumors. [6]
Treatment is usually surgical, followed by radioiodine.
Some studies have shown that thyroglobulin (Tg) testing combined with neck ultrasound is more productive in finding disease recurrence than full- or whole-body scans (WBS) using radioactive iodine. However, current protocol (in the USA) suggests a small number of clean annual WBS are required before relying on Tg testing plus neck ultrasound. When needed, whole body scans consist of withdrawal from thyroxine medication and/or injection of recombinant human Thyroid stimulating hormone (TSH). In both cases, a low iodine diet regimen must also be followed to optimize the takeup of the radioactive iodine dose. Low dose radioiodine of a few millicuries is administered. Full body nuclear medicine scan follows using a gamma camera. Scan doses of radioactive iodine may be I131 or I123.
Recombinant human TSH, commercial name Thyrogen, is produced in cell culture from genetically engineered hamster cells.
The overall 5-year survival rate for follicular thyroid cancer is 91%, and the 10-year survival rate is 85%. [8]
By overall cancer staging into stages I to IV, follicular thyroid cancer has a 5-year survival rate of 100% for stages I and II, 71% for stage III, and 50% for stage IV. [9]
Compared to other variants of Follicular cell derived thyroid cancer, bone metastases are commonly associated with follicular carcinoma. In the present study a high rate of bone metastases of 34% was observed. [10]
Thyroid neoplasm is a neoplasm or tumor of the thyroid. It can be a benign tumor such as thyroid adenoma, or it can be a malignant neoplasm, such as papillary, follicular, medullary or anaplastic thyroid cancer. Most patients are 25 to 65 years of age when first diagnosed; women are more affected than men. The estimated number of new cases of thyroid cancer in the United States in 2023 is 43,720 compared to only 2,120 deaths. Of all thyroid nodules discovered, only about 5 percent are cancerous, and under 3 percent of those result in fatalities.
Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesodermal or ectodermal germ layer during embryogenesis.
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.
An oncocytoma is a tumor made up of oncocytes, epithelial cells characterized by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. The cells and the tumor that they compose are often benign but sometimes may be premalignant or malignant.
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.
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.
Toxic multinodular goiter (TMNG), also known as multinodular toxic goiter (MNTG), is an active multinodular goiter associated with hyperthyroidism.
Hürthle cell neoplasm is a rare tumor of the thyroid, typically seen in women between the ages of 70 and 80 years old. When benign, it is called a Hürthle cell adenoma, and when malignant it is called a Hürthle cell carcinoma. Hürthle cell 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 of Hürthle cell carcinoma, which is a subtype of follicular thyroid cancer.
Papillary thyroid cancer 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.
The sodium/iodide cotransporter, also known as the sodium/iodide symporter (NIS), is a protein that in humans is encoded by the SLC5A5 gene. It is a transmembrane glycoprotein with a molecular weight of 87 kDa and 13 transmembrane domains, which transports two sodium cations (Na+) for each iodide anion (I−) into the cell. NIS mediated uptake of iodide into follicular cells of the thyroid gland is the first step in the synthesis of thyroid hormone.
A thyroid adenoma is a benign tumor of the thyroid gland, that may be inactive or active as a toxic adenoma.
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.
Paired box gene 8, also known as PAX8, is a protein which in humans is encoded by the PAX8 gene.
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.
The Bethesda system (TBS), officially called The Bethesda System for Reporting Cervical Cytology, is a system for reporting cervical or vaginal cytologic diagnoses, used for reporting Pap smear results. It was introduced in 1988 and revised in 1991, 2001, and 2014. The name comes from the location of the conference, sponsored by the National Institutes of Health, that established the system.
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.
Squamous-cell carcinoma of the thyroid (SCT), or thyroid squamous-cell carcinoma, is rare malignant neoplasm of thyroid gland which shows tumor cells with distinct squamous differentiation. The incidence of SCT is less than 1% out of thyroid malignancies.
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 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 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 the 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.
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