Thyroid nodule
Encyclopedia
Thyroid nodules are lumps which commonly arise within an otherwise normal thyroid gland. They indicate a thyroid neoplasm, but only a small percentage of these are thyroid cancer
Thyroid cancer
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...

s.

Presentation

Often these abnormal growths of thyroid tissue are located at the edge of the thyroid gland so they can be felt as a lump in the throat. When they are large or when they occur in very thin individuals, they can even sometimes be seen as a lump in the front of the neck.

Sometimes a thyroid nodule presents as a fluid-filled cavity (called a thyroid cyst). Often, solid components are mixed with the fluid. Thyroid cysts most commonly result from degenerating thyroid adenoma
Thyroid adenoma
-Types:Almost all thyroid adenomas are follicular adenomas. Follicular adenomas can be described as "cold", "warm" or "hot" depending on their level of function...

s, which are benign, but they occasionally contain malignant solid components.

Diagnosis

After a nodule
Nodule (medicine)
For use of the term nodule in dermatology, see Nodule In medicine, a nodule refers to a relatively hard, roughly spherical abnormal structure....

 is found during a physical examination, a referral to an endocrinologist, a thyroidologist
Thyroidologist
A thyroidologist is a medical practitioner specializing in the thyroid and related areas.In the United States it refers to a board certified endocrinologist physician, who is either a full time academician with multiple responsibilities beside thyroid patient care, or a clinical thyroidologist...

 or otolaryngologist may occur. Most commonly an ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 is performed to confirm the presence of a nodule, and assess the status of the whole gland. Measurement of thyroid stimulating hormone and anti-thyroid antibodies will help decide if there is a functional thyroid disease such as Hashimoto's thyroiditis
Hashimoto's thyroiditis
Hashimoto's thyroiditis or chronic lymphocytic thyroiditis is an autoimmune disease in which the thyroid gland is gradually destroyed by a variety of cell- and antibody-mediated immune processes. It was the first disease to be recognized as an autoimmune disease...

 present, a known cause of a benign nodular goiter. Fine needle biopsy for histopathology
Histopathology
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...

 is also used.

Thyroid nodules are extremely common in young adults and children. Almost 50% of people have had one, but they are usually only detected by a GP during the course of a health examination, or through a different affliction.

Fine needle biopsy

One approach used to determine whether the nodule is malignant is the fine needle biopsy (FNB), which some have described as the most cost-effective, sensitive and accurate test.
FNB or ultrasound-guided FNA usually yields sufficient thyroid cells to assess the risk of malignancy, although in some cases, the suspected nodule may need to be removed surgically for pathological examination.

Rarely, a biopsy is done using a large cutting needle, so that a piece of nodule capsule can be obtained.

Blood tests

Blood or imaging tests may be done prior to or in lieu of a biopsy. The possibility of a nodule which secretes thyroid hormone (which is less likely to be cancer) or hypothyroidism is investigated by measuring thyroid stimulating hormone (TSH), and the thyroid hormones thyroxine
Thyroxine
Thyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.-Synthesis and regulation:...

 (T4) and triiodothyronine
Triiodothyronine
Triiodothyronine, C15H12I3NO4, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate....

 (T3).

Tests for serum thyroid autoantibodies are sometimes done as these may indicate autoimmune thyroid disease (which can mimic nodular disease).

Imaging

The blood assays may be accompanied by ultrasound
Medical ultrasonography
Diagnostic sonography is an ultrasound-based diagnostic imaging technique used for visualizing subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions...

 imaging of the nodule to determine the position, size and texture, and to assess whether the nodule may be cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...

ic (fluid filled). Also suspicious findings in a nodule are hypoechoic, irregular borders, microcalcification
Microcalcification
Microcalcifications are tiny specks of mineral deposits , that can be scattered throughout the mammary gland, or occur in clusters. When found on a mammogram, a radiologist will then decide whether the specks are of concern - usually, this is not the case...

s, or very high levels of blood flow within the nodule. Less suspicious findings in benign nodules include, hyperechoic, comet tail artifacts from colloid
Colloid
A colloid is a substance microscopically dispersed evenly throughout another substance.A colloidal system consists of two separate phases: a dispersed phase and a continuous phase . A colloidal system may be solid, liquid, or gaseous.Many familiar substances are colloids, as shown in the chart below...

, no blood flow in the nodule and a halo
Halo (optical phenomenon)
A halo from Greek ἅλως; also known as a nimbus, icebow or gloriole) is an optical phenomenon produced by ice crystals creating colored or white arcs and spots in the sky. Many are near the sun or moon but others are elsewhere and even in the opposite part of the sky...

, or smooth border.

Some clinicians will also request technetium
Technetium
Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...

 (Tc) or radioactive iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

 (I) imaging
Scintigraphy
Scintigraphy is a form of diagnostic test used in nuclear medicine, wherein radioisotopes are taken internally, and the emitted radiation is captured by external detectors to form two-dimensional images...

 of the thyroid. An 123I scan showing a hot nodule, accompanied by a lower than normal TSH, is strong evidence that the nodule is not cancerous.

Malignancy

Only a small percentage of lumps in the neck are malignant, and most thyroid nodules are benign.

There are many factors to consider when diagnosing a malignant lump.

If the patient is a smoker, the chances of malignancy are considerably higher. When coupled with difficulty swallowing or breathing, this may be a symptom of a serious condition and requires speedy medical attention.

Risks for cancer

Solitary thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...

 nodules are more common in females yet more worrisome in males. Other associations with neoplastic nodules are family history of thyroid cancer
Thyroid cancer
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...

 and prior radiation to the head and neck.

Radiation exposure to the head and neck may be for historic indications such as tonsillar and adenoid hypertrophy, "enlarged thymus", acne vulgaris, or current indications such as Hodgkin's lymphoma. Children living near the Chernobyl
Chernobyl
Chernobyl or Chornobyl is an abandoned city in northern Ukraine, in Kiev Oblast, near the border with Belarus. The city had been the administrative centre of the Chernobyl Raion since 1932....

 nuclear power plant during the catastrophe of 1986 have experienced a 60-fold increase in the incidence of thyroid cancer. Thyroid cancer arising in the background of radiation is often multifocal with a high incidence of lymph node metastasis and has a poor prognosis.

Signs and symptoms

Worrisome sign and symptoms include voice hoarseness, rapid increase in size, compressive symptoms (such as dyspnoea or dysphagia) and appearance of lymphadenopathy
Lymphadenopathy
Lymphadenopathy is a term meaning "disease of the lymph nodes." It is, however, almost synonymously used with "swollen/enlarged lymph nodes". It could be due to infection, auto-immune disease, or malignancy....

.

Investigations

  • TSH
    TSH
    TSH may refer to:* Tanzanian shilling, the currency of Tanzania* Thyroid-stimulating hormone, a hormone synthesized and secreted by thyrotrope cells* Tshiuetin Rail Transportation, a Canadian railway between Labrador and Quebec...

     - A thyroid-stimulating hormone level should be obtained first. If it is suppressed, then the nodule is likely a hyperfunctioning (or "hot") nodule. These are rarely malignant.
  • FNAC - fine needle aspiration cytology
    Needle aspiration biopsy
    Needle aspiration biopsy , may refer to fine needle aspiration cytology , fine needle aspiration biopsy and fine needle aspiration , is a diagnostic procedure sometimes used to investigate superficial lumps or masses...

     is the investigation of choice given a non-suppressed TSH. Repeat the FNAC in 6 months if the nodule enlarges.
  • Imaging - Ultrasound
    Ultrasound
    Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

     and radioiodine scanning.

Thyroid Scan

Cold - 85% of nodules are cold. 5-8% of cold and warm nodules are malignant.

Hot - 5% of nodules are hot. Among these, 1% are malignant.

Surgery

Surgery should be performed in the following instances
  • Reaccumulation of the nodule despite 3-4 repeated FNACs
  • Size in excess of 4 cm in some cases
  • Compressive symptoms
  • Signs of malignancy (vocal cord dysfunction, lympadenopathy)
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