Thyroid Nodules

March 30, 2019

Definition

A thyroid noduleis defined as a small lump of tissue (either solid or cystic - filled with fluid), usually more than one quarter of an inch in diameter that may protrude from the neck's surface or may form in the thyroid gland itself. The nodule can be either benign (non-cancerous) or malignant (cancerous).

Causes

Even though the incidence of thyroid nodules (4 to 7 percent of the population) and thyroid cancer (1 percent of the population) is rare, there are certain risk factors that could make a person susceptible tothyroid cancer. The risk factors are:

男性
Age - Less than 20 years of age or over 60 years of age
Exposure to ionizing radiation, especially in childhood
A family history of thyroid cancer

Symptoms

Most people are asymptomatic (no symptoms) when thyroid nodules are first discovered. However, a noticeable lump or enlarged lymph nodes in neck may be an indication of a thyroid-related problem. More severe symptoms, such as thyroid pain, difficulty in swallowing, hoarseness or vocal cord paralysis and airway obstruction may be an indication of a possible malignant thyroid tumor.

Diagnosis

The diagnosis a thyroid nodule is made by asking questions about risk factors and underlying health, a physical examination, a laboratory test called TSH, diagnostic imaging and fine-needle aspiration (FNA).

物理检查包括检查甲状腺，以进行可能的放大（通常称为甲状腺肿），其相邻的淋巴结，用于任何疼痛，压痛和肿胀，以及用于一致性，大小和质地的结节本身。如果结节柔软，光滑和移动，那么结节是良性的。如果结节坚固，硬，不规则和固定，结节可能是恶性的。

TSH（甲状腺刺激激素）血液试验给予甲状腺功能，并确定甲状腺炎的超（甲状腺过度腺体）的存在和（甲状腺的不动）甲状腺。

Diagnostic imaging may include ultrasonography of the thyroid gland as well as radionuclide scanning (called a thyroid scan). Ultrasonography or ultrasound is used to determine if the nodule is solid or cystic and how many nodules there are. It cannot determine if the nodule is benign or malignant, but it is a good indicator of whether a nodule is increasing or decreasing in size. The thyroid scan is used to provide information about the location, anatomy and the function of the thyroid gland.

For the thyroid scan, an injection or an oral dose of a radioisotope substance is given. The radioisotope substance usually contains a tiny dose of specially prepared technetium or radioiodine that is absorbed by the thyroid tissue. In this procedure there are two classifications of thyroid nodules - "hot" and "cold" - depending on the absorption of the radioiodine determines the classification.

A hot nodule is one that concentrates radioiodine equal to or more than the surrounding thyroid tissue. Occasionally, the rest of the thyroid is not even visible on the scan because the hot nodule is making so much thyroid hormone that the function of the rest of the thyroid gland is suppressed. Hot nodules are never malignant.

一种浓缩碘或根本不浓缩碘的结节被称为寒冷。虽然所有癌症都是寒冷的，但大多数良性肿瘤和囊肿也很冷。事实上，只有大约10％的孤零性冷结节被证明是恶性的，然而，冷结节的存在始终是进一步评估的指示。

Needle aspiration is the most effective method for distinguishing benign and malignant thyroid nodules. This procedure involves numbing the skin over the nodule and inserting a tiny needle into the nodule for 10 to 60 seconds to obtain thyroid tissue for microscopic examination.

治疗

Individuals who are found to have thyroid cancer, or in whom the tissue samples are not adequate to exclude cancer, need to have their nodules removed surgically. This procedure is called athyroidectomy.

Patients with benign thyroid nodules should be monitored periodically or treated with levothyroxine to suppress the nodule growth.

Indeterminate nodules should be removed if there is clinical suspicion of malignancy. In suspect nodules, levothyroxine therapy with follow-up ultrasound assessment for size is appropriate. Nodules that do not shrink significantly within six months should be removed.