Early thyroid cancer is usually asymptomatic, and more than half of patients are now being seen on physical examination when a lump is detected by ultrasound of the neck.
When the tumor is small and confined to the thyroid gland, there is usually no clinical manifestation. When the tumor gradually increases in size, breaks through the envelope, or develops lymph node metastases or distant metastases, the corresponding clinical manifestations will occur. The details are as follows.
Symptoms of the primary focus
A primary site of thyroid cancer may present as a painless mass or nodule in the front of the neck. An experienced physician may be able to initially determine the nature of the nodule by its texture, smoothness, and growth rate.
Some signs that suggest a malignant nodule include:
- The general absence of pressure pain;
- When the surface of the mass is carefully touched with the thumb and index finger, it can be felt as hard in texture, with an uneven (bumpy) surface and fuzzy edges;
- The mass usually moves up and down with swallowing, but if it invades the trachea or surrounding tissues, the mass becomes “fixed” and no longer moves with swallowing movements;
- Malignant tumors may increase in size over a relatively short period of time.
Local pressure symptoms
When a thyroid mass compresses the trachea, it can lead to narrowing and deformation of the trachea, and over time, even to softening of the trachea. Patients may experience shortness of breath, dyspnea, hemoptysis, and a feeling of suffocation in the chest.
When a mass compresses the esophagus, the less severe cases experience discomfort and choking, and the more severe cases are unable to eat. In the long term, patients can suffer from malnutrition and weight loss.
Local invasive symptoms
Invasion is a unique growth pattern for malignant tumors.
When a thyroid tumor is more malignant or has been present for a longer period of time, the lesion may break through the envelope of the thyroid gland and invade surrounding tissues and structures. The most vulnerable sites include the laryngeal recurrent nerve, larynx, trachea, esophagus, and parathyroid glands.
The recurrent laryngeal nerve is the main motor nerve in the larynx and innervates most of the muscles in the larynx. It is most susceptible to invasion because it lies immediately dorsal to the thyroid gland. When thyroid cancer irritates or invades the recurrent laryngeal nerve, it affects its function and patients experience symptoms such as choking on water and hoarseness.
When the tumor invades the esophagus, there may be difficulty swallowing and there may be vomiting of blood due to tumor bleeding.
When the tumor invades the larynx and trachea, it may also cause symptoms such as dyspnea and hemoptysis.
Metastatic symptoms
1. Lymph node metastasis in the neck
When a patient with thyroid cancer has swollen lymph nodes in the neck, it may be due to metastasis of the cancer. These swollen lymph nodes are usually not painful. If the lymph nodes in the neck are hard and fixed and cannot be pushed, it is highly suggestive of lymph node metastasis.
The lymph nodes around the thyroid and in the ipsilateral lower neck are most likely to be invaded.
2. Distant metastases
Differentiated thyroid cancer is less likely to develop blood metastases; whereas hypofractionated and undifferentiated thyroid cancer are more likely to develop distant metastases.
Less than 10% of papillary thyroid carcinomas (PTC) develop distant metastases. The most common site of metastasis is the lung, followed by the bone.
Whatever organ the thyroid cancer metastasizes to will have the appropriate symptoms:
- Lung or chest metastases, causing cough, hemoptysis and chest discomfort;
- Bone metastases are found in the spine, ribs, and pelvis, and tend to cause pathological fractures, pain, and compression symptoms;
- Brain metastases are mostly found in the brain and rarely in the cerebellum, causing headache and dizziness, visual impairment, epilepsy, motor-sensory impairment, nausea and vomiting, and mental abnormalities.
Neuroendocrine symptoms
Medullary thyroid cancer (MTC) is a relatively specific type of thyroid cancer. The cancer cells secrete a variety of hormones and biogenic amines, and these biotin cause diarrhea, palpitations, flushing of the face, and decreased blood calcium (manifested by numbness in the hands and feet and twitching of the extremities), among other manifestations.
Some patients with thyroid cancer even present first with gastrointestinal symptoms, such as recurrent diarrhea, without significant abnormalities on gastroscopy. Some MTC with concurrent pheochromocytoma and parathyroid hyperplasia or tumors may also present with symptoms such as urinary tract stones and gallstones.
Co-Author: Cancer Hospital of Fudan University Dr. Kai Qian