Synonyms in the broadest sense
Thyroid malignancy, malignant tumors of the thyroid gland, papillary thyroid carcinoma, follicular thyroid carcinoma, anablastic thyroid carcinoma, medullary thyroid carcinoma
Definition
Malignant tumors of the thyroid gland are thyroid carcinomas in 95% of cases, which can occur in different forms. Carcinomas are tumors that originate from epithelial cells of the thyroid gland. Tumors that originate from other cell types are very rare (approx. 5%), as are metastases in the thyroid gland that are spread by other primary tumors (= original tumor). Four different forms of carcinoma are distinguished, which can be differentiated from each other with the help of the following criteria: The cell structure of the tumor is assessed, the tendency to form tumor metastases in the tissue and the prognosis associated with the tumor type.
EpidemiologyResources
Thyroid cancer occurs only rarely: 3 out of 100,000 inhabitants in Europe suffer from a malignant thyroid tumor every year. In Europe, thyroid carcinomas are therefore relatively rare; a higher rate of the disease is found in China, Hawaii and in the area around Chernobyl. Malignant tumors of the thyroid gland are the eleventh most frequent cause of death caused by cancer.
CauseEstablishment
An important factor in the development of malignant thyroid tumors is the exposure of the affected person to ionizing radiation (e.g. X-rays). In addition, genetic components are responsible as predisposing factors for the development of malignancies. The damage to the genetic material in the thyroid cells leads to unhindered autonomous growth, which is no longer subject to the control of hormone regulatory cycles.
Due to the enlarged thyroid gland, adjacent structures are compressed, so that swallowing disorders can occur, hoarseness occurs because the vocal fold controlling nerve takes its course near the thyroid gland or there is an upper influence congestion. If there is an upper influence congestion, the venous blood can only flow back to the heart through the compressed neck vessels to a limited extent; the compression of the vessels is caused by the enlargement of the thyroid gland. Sore throat and retraction of the skin over the thyroid gland are possible signs of a malignant process in the thyroid.
The signs of thyroid cancer are manifold and in no way specific to this particular type of cancer. In many cases, a marked swelling of the neck lymph nodes in the area of the thyroid gland is described. However, this can also be attributed to a harmless cold or flu-like infection.
In addition, many thyroid cancer patients experience an increase in the size of the thyroid gland, also known as goiter or struma formation. However, the symptom “goiter” is not a clear indication of the presence of cancer. Overactive thyroid (hyperthyroidism) or underactive thyroid (hypothyroidism) as well as benign cyst formation can also lead to conspicuous growth of the organ.
However, the first signs of thyroid cancer appear quite late, when they manifest themselves in the form of functional limitations of the neighboring organs after a strong increase in volume of the thyroid gland or as a palpable lump through the skin. This is only the case when the cancer has a certain diameter of at least 1.5-2cm and is therefore palpable, but not yet visible and without symptoms. When the cancer has reached a certain size, it is possible that it presses on the trachea or the esophagus, thus impeding the passage of air or food.
Patients then usually complain of shortness of breath and difficulty swallowing. The cancer can also impair the function of the laryngeal nerves, which are responsible for vocal fold activity. Depending on the degree of restriction, unilateral or bilateral vocal fold paralysis occurs, which can cause signs such as hoarseness, coughing or even shortness of breath (in the case of vocal folds paralyzed on both sides).
If there is a functional impairment of the central nerve tracts of the sympathetic nervous system, even the so-called Horner Trias can occur. These are three typical signs in the area of the eyes:
- Narrowed pupils (miosis)
- Drooping upper eyelids at the eyes (ptosis) and
- Sunken eyeballs (enophthalmus).
The most common types of thyroid cancer, papillary or follicular, manifest themselves primarily in markedly swollen cervical lymph nodes, as they usually spread through the lymphatic system and begin to spread in the local lymph nodes of the neck. Medullary thyroid cancer (also called C-cell cancer because it starts from the C-cells of the thyroid gland) causes hypocalcemia (low blood calcium levels) due to elevated levels of calcitonin.
The C-cells of the thyroid gland are responsible for the production of calcitonin, which regulates the calcium and phosphate levels in the body. When these cells degenerate, more calcitonin is produced. The resulting signs of hypocalcemia are muscle cramps and numbness in the form of tingling in the fingertips and toes.
Diarrhea is also described by some patients. Anaplastic thyroid cancer, on the other hand, has a more aggressive growth pattern, which leads to early onset of symptoms such as asymmetrical swelling of the neck, reddening of the skin, hoarseness and difficulty swallowing. All in all, most diagnoses are chance findings that were discovered during a preventive ultrasound examination by a dermatologist. Since thyroid cancer does not show any specific signs and all symptoms that occur only become apparent very late, it is recommended that a routine ultrasound of the neck and thyroid gland be performed regularly.
