Thyroid Tumors and Nodules in Children

In this article, we will talk about Thyroid Tumors, which are thyroid pathologies that require surgery in children. Since they have been encountered more frequently in Pediatric Surgery Clinics recently, we will talk about tumors. Very rare surgical diseases of the thyroid, such as goiter and other internal diseases, will not be discussed.

What is the Thyroid Gland and Its General Function?

The thyroid gland is located just below the cartilage called the Adam's apple in our neck and in front of the trachea. It is butterfly-shaped. It has two sections, right and left. These are called the thyroid lobe. These two lobes are connected to each other by a thin tissue band called the isthmus. Under normal conditions, the thyroid gland is not visible to the eye and is not easily felt by hand.

What are the Functions of the Thyroid Gland?

The function of the thyroid gland is to produce Thyroid hormones (T3 and T4 hormones). The raw material of these hormones is the iodine atom. The thyroid gland produces T3 and T4 using the iodine atom. The T4 hormone is actually the storage form of the T3 hormone, which is the main effect. Before entering the cell where it will be effective, the T4 hormone releases an iodine atom and transforms into the main effect T3 hormone and performs its function through these hormones.

Thyroid hormones regulate the functions of every cell and tissue in our body. Thus, thyroid hormones play a determining role in the speed of the entire metabolism. In order to be healthy, thyroid hormones must be secreted continuously and in sufficient amounts. Secretion in small amounts causes body functions to slow down, while secretion in large amounts causes body functions to accelerate. After the hormones produced in the thyroid gland pass into the blood, 99% of them circulate by binding to carrier proteins. These hormones are directly or indirectly effective on many systems. For example: Gastrointestinal System, Cardiovascular System, Eye etc.

Thyroid Gland Cancers in Children:

Surgical diseases related to the thyroid gland are quite rare in childhood. The most common thyroid disease in this period is simple goiter, followed by thyroid nodule. The estimated frequency of thyroid nodules is 1-1.5% in young children and 13% in adolescents. The probability of thyroid nodules being malignant is 5% in adults, while it is 22-26% in children.

Cancers originating from the thyroid gland are the most common endocrine tumors and constitute 0.3-2.7% of childhood cancers. The incidence increases between the ages of 9-14, and 2/3 of cases are girls. It is at least 4 times more malignant than adults.

The incidence of thyroid cancer in adolescents is 10 times higher than in younger children, and the female/male ratio in this age group is 5/1. There is no difference in frequency between girls and boys in younger children. According to some studies, the spread of thyroid gland to surrounding tissues, lymph nodes and lungs at the time of diagnosis is more common before puberty.

Are There Causes of Thyroid Cancer in Children?

It is known that some factors will be effective, although it is not certain. For example; Radiation, Chemotherapy (for example, chemotherapy received due to Lymphoma), Autoimmune Diseases (Hashimoto's Thyroiditis), Genetic predisposition (Medullary Thyroid Cancer, Multiple Polyposis Coli ..).

Are There Types of Thyroid Cancer in Children?

Yes, there are. Malignant tumors of the thyroid are divided into 4 main groups according to their histopathological features and clinical behavior. These are;

1. Papillary thyroid carcinoma
2. Follicular thyroid carcinoma
3. Medullary thyroid carcinoma
4. Anaplastic thyroid carcinoma

Papillary thyroid carcinoma is the most common in both children and adults. It constitutes 85-90% of thyroid cancers. It is the type of carcinoma with the slowest clinical course.

• Follicular thyroid carcinoma, unlike adults, is rare in children and is more common in adolescence.
• Medullary thyroid cancer accounts for 5% of pediatric thyroid cancer cases. It originates from parafollicular C cells. They secrete calcitonin and are important in the diagnosis and follow-up of the tumor. They are components of MEN 2A and 2B syndromes.

Lymph node metastasis, spread outside the thyroid capsule, and lung metastases (spread) are common in thyroid carcinomas seen in children. Histopathologically, cervical lymph node metastasis (spread) is found in 80-90% of patients at the time of diagnosis.

What are the Clinical Findings of Thyroid Cancer in Children?

The most common finding in patients is a painless swelling in the neck. Swelling in the neck is often cervical lymphadenopathy. Local symptoms such as respiratory tract obstruction, hoarseness, and dysphagia are usually together with thyroid nodules and goiter and can only be seen in 5% of thyroid carcinoma cases. Since thyroid cancer in children will spread to the cervical lymph nodes more quickly than in adults, it should definitely be considered in children presenting with lymph node enlargement.

The probability of malignancy in thyroid masses increases as the age of diagnosis decreases. At the time of diagnosis, 80-90% of children have lymph node metastasis (paratracheal, delphian and supramediastinal lymph nodes are frequently involved). Lung metastasis is detected in 18-25%. (AC involvement without lymph node involvement is rare), both lymph node and lung metastasis are more common than in adults.

Multiple foci have been reported in 26-85% of thyroid carcinomas. Disease has also been found in the contralateral lobe in 30-80% of patients.

 

How is Thyroid Cancer Diagnosed in Children?

It is diagnosed by history and physical examination and confirmed by imaging methods and tests. Since thyroid cancers in children generally do not synthesize hormones, there are no other findings other than the findings described above, for example, there are no sweating, tachycardia, etc. findings seen in classic goiter, but weight loss is seen due to cancer.

Ultrasound; It is a harmless and cheap method. Thyroid ultrasonography is helpful in detecting non-palpable nodules and sometimes in differentiating benign from malignant nodules. The size of the thyroid nodule, its irregular edges, calcium deposits and increased blood flow are indicative of malignancy. It also allows the distinction of cystic or solid lesions.

Scintigraphy

• In imaging studies of the thyroid gland, it is most commonly used in the diagnosis and treatment of thyroid carcinoma metastases.
• Thyroid nodules are divided into three groups according to their ability to concentrate iodine in scintigraphy: ‘hot, cold and warm’.
• While cold nodules are mostly malignant, hot and warm nodules also have the potential to become malignant.

Fine needle aspiration biopsy

• It is a reliable and inexpensive method for the diagnosis of nodular diseases of the thyroid and for the selection of patients who will undergo surgical treatment.
• The diagnostic accuracy rate is 95% in terms of differentiating between benign and malignant lesions.
• Fine needle aspiration biopsy has almost no complications. However, children may not be as sensitive as adults in terms of diagnosis.

Thyroglobulin

• A protein secreted from the thyroid gland.
• It increases in inflammatory events or any damage to the thyroid.
• It can be used as a tumor marker for both diagnosis and follow-up in cases where thyroidectomy has been performed.
• It is the most sensitive tumor marker used in monitoring thyroid cancers. Measuring TG in the postoperative period provides information on whether the surgery was completely successful.

What is the Treatment of Childhood Thyroid Cancer?

The first and most effective treatment option for thyroid carcinomas is surgery. However, alone or in combination with surgery, radioactive iodine therapy, hormone replacement, radiotherapy and hormone replacement can be used in the treatment. Especially in cases with distant metastases such as lungs at the time of diagnosis, radioactive iodine should be used for the treatment of metastasis. However, the main method of treatment is surgery.

Are There Complications of Thyroid Surgery?

Yes, there are. The thyroid gland is located in an area where veins and nerves pass widely in the neck. Therefore, there may be serious temporary and permanent complications during and after surgery. The most common temporary complications are; Fluid accumulation in the area of ​​surgery (Seroma), Bleeding, Hoarseness and Respiratory failure, and Calcium deficiency and related contractions. Hoarseness and hypocalcemia may be permanent.

Is Complete Removal of the Thyroid Necessary in Papillary Thyroid Cancer?

Yes, it is necessary, and even if the tumor has spread to the neck lymph nodes, this is not enough.

Is Complete Removal of the Thyroid Sufficient in Papillary Thyroid Cancer?

If the tumor has spread beyond the thyroid gland and the neck glands are involved, it is not enough. In these cases, a surgery called neck dissection is performed. Neck dissection surgeries are quite risky and require experience. In general, all soft tissues in the neck region, except for the nerves, veins and muscles, including the lymph nodes, must be removed. It is a very long and risky surgery.

Does Complete Removal of the Thyroid Gland Require Lifelong Thyroid Hormone Reception?

Yes, the patient must take thyroid hormone for life, and even accidental or forced removal of the parathyroid glands requires lifelong calcium intake.

Is Additional Treatment Required After Surgery in Papillary Thyroid Cancer?

If the cancer has not spread beyond the thyroid gland and the thyroid gland has been completely removed properly, it is not required. However, if it has spread to the neck lymph nodes, it is required. For this, Radioactive Iodine treatment and sometimes Radiotherapy may be required. This depends entirely on the timing of diagnosis and whether the surgery is performed properly.

How is Thyroid Nodule Approached?

 

Iodine deficiency, exposure to radiation, some genetic syndromes (such as familial adenomatous polyposis, Gardner syndrome, Turcot syndrome) and previous thyroid disease are known risk factors for the development of thyroid nodules. Cancer patients who received radiotherapy during their primary treatment and survived; especially those treated for Hodgkin lymphoma, leukemia and central nervous system tumors are at high risk for the development of thyroid nodules. There are publications showing that the frequency of thyroid nodule development in children with autoimmune thyroiditis is up to 30%.

Annual physical examination is recommended for children at risk for the development of thyroid cancer. Imaging methods can be used in the presence of palpable nodules, thyroid asymmetry or lymphadenopathy in the neck.

In cases with thyroid nodules, serum T4 and TSH levels should be examined in addition to the history and physical examination. In particular, familial predisposition and exposure to radiation should be examined in the history. In physical examination, the structure and size of the thyroid gland, whether it is sensitive or not, the size, consistency, number of the nodule, and whether there is enlargement in regional lymph nodes should definitely be noted.

Imaging methods are of limited help in childhood. Ultrasonography (US) can provide information about the structure of the thyroid gland, the size of the nodule, whether it is solid or cystic, its number, and the size and structure of the lymph nodes in the neck. However, US is of limited help in distinguishing between benign and malignant. In the presence of the US findings given in Table 1, it should be kept in mind that thyroid nodules and lymph nodes may be malignant. Thyroid scintigraphy also provides information about the function of the thyroid nodule, but its help in distinguishing between benign and malignant is limited.

Table 1. Ultrasonographic findings related to malignancy in thyroid nodules and lymph nodes.

If the thyroid nodule is solid or solid-cystic and larger than 1 cm or if the ultrasonographic (US) features raise suspicion of malignancy, treatment is determined according to the results of fine needle aspiration biopsy (FNAB).

The evaluation of thyroid nodules in children should be the same as in adults, except for the following differences:

• When deciding on the need for FNAB, US features and clinical data should be considered rather than the size of the nodule.
• All FNABs in children should be performed under US guidance.
• Since surgical excision of hyperfunctioning nodules will be planned, preoperative FNAB is not necessary.
• Papillary thyroid cancer in children can be extensively infiltrative, and FNAB should be performed in clinically suspicious thyroids.
• In nodules with non-descript cytological findings, lobectomy with isthmus removal and pathological examination should be preferred instead of re-biopsy.
• In the presence of a nodule in the thyroid, if TSH is suppressed (below normal value), thyroid scintigraphy should be performed, and in the presence of a hyperfunctioning nodule, the thyroid lobe where the nodule is located should be removed together with the isthmus. If hyperthyroidism findings are subclinical, surgery can be postponed, but if there are suspicious findings in the nodule (nodule ≥1 cm, ultrasonography findings indicating malignancy), FNAB should be performed.

If TSH is not suppressed and there is a suspicious nodule in the thyroid (nodule ≥1 cm, US findings indicating malignancy) or if the nodule is hypofunctioning in the presence of TSH suppression, FNAB should be performed (Figure 1).

FNAB is evaluated as non-diagnostic or insufficient, benign, atypia or follicular lesion of uncertain significance, follicular/Hurthle cell neoplasia or suspicious follicular/Hurthle cell neoplasia, supporting malignancy and malignant.

If the FNAB result is benign, US should be performed after 6-12 months; if the nodule is stable, US should be repeated every 1-2 years. If there is growth in the nodule or suspicious changes in the findings, FNAB should be repeated or surgery should be preferred (3).

If the FNAB result is insufficient or non-diagnostic, US and FNAB should be repeated within 3-6 months. If the nodule is found to be stable or benign, US should be repeated within 6-12 months. However, if the nodule is growing or the FNAB result suggests that the nodule is not benign, surgery should be preferred.

In patients with suspicious or uncertain FNAB and who will undergo surgery, the lobe where the nodule is located should be removed with the isthmus and a frozen biopsy should be performed; if the result is malignant, total thyroidectomy should be performed. If the frozen biopsy result is benign or suspicious, the surgery should be terminated and the definitive pathology result should be awaited. Depending on the pathology result, complementary thyroidectomy ± radioactive iodine therapy ± TSH suppression may be required. If a definitive pathological diagnosis is not obtained within a week, complementary surgery may be postponed for one month due to adhesions in the neck.

*** The information provided here and the content of the website are designed to inform visitors, especially families. No information should be considered as advice by visitors and should not lead to any decision or action. Families should definitely have their patients examined by a pediatric surgeon, consult with him/her and make a decision based on his/her personal knowledge.