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Thymus Gland Cancer

The thymus gland, commonly referred to as the thymus, has important functions in the body. As an indispensable organ of the immune system, the thymus gland is larger during childhood and becomes much smaller during adolescence. Cancer, one of the most serious diseases of our time, can also occur in the thymus gland. However, thymus gland cancers constitute one of the rarest types of cancer among all cancers.

The most common type of thymus gland cancer is known as thymoma tumor. Thymoma tumor is a very slow-progressing disease, which means that the patient's life expectancy can be longer compared to other types of cancer. The exact cause of thymus gland cancer is not yet fully understood. As with any disease, early detection of thymus gland cancer and proper treatment planning are crucial for the quality and duration of a patient's life.

The Department of Thoracic Surgery of Uniqacare Clinic provided information about the thymus gland, thymus gland cancers, the causes of thymus gland cancer, and treatment methods.

What is thymus gland?

The thymus gland is located behind the breastbone in the front of the windpipe, just below the thyroid gland, and in front of the heart. Resembling the letter "H," the thymus gland is a small, encapsulated organ that is pinkish-grey in color. It is relatively large at birth but tends to shrink and become less visible during adolescence. In older adults, it is estimated to weigh around 5 grams. In male children, the thymus gland is slightly larger in size compared to female children, and it can be seen on X-rays in children up to the age of 3. Although the thymus gland may become less visible as it shrinks after adolescence, it continues to function throughout one's lifetime.

What is the role of thymus gland?

The thymus gland, one of the lesser-known organs in the body, plays important roles. It is a vital part of the immune system and is fully developed at birth. The thymus gland is responsible for producing one of the key components of the immune system, T cells. It also produces antibodies against microorganisms that are foreign to the body. The thymus gland is part of both the lymphatic and endocrine systems, along with the tonsils, adenoids, and spleen. T cells, which are essential for eliminating infected or cancerous cells in the body, are produced by the thymus gland. These T cells created by the thymus gland also help ensure the proper growth of other organs in the immune system.

What is thymus gland cancer?

Thymus gland cancer is a rare type of cancer. There are two types of cancers that can occur in the thymus gland. The most common type of cancer in the thymus gland is called thymoma cancer. The other rare type of cancer that can occur in the thymus gland is called thymic carcinoma.

What are thymic carcinoma tumors?

Thymic carcinoma tumors are the rarest type of thymus gland cancer. Thymic carcinoma tumors tend to grow more quickly and can spread to other parts of the body more rapidly. Therefore, treating thymic carcinoma tumors is more challenging. Having thymic carcinoma in combination with autoimmune conditions is much rarer than with thymoma.

What is a thymoma tumor?

Thymoma is the most common tumor originating from the thymus gland in adults. This malignancy is very rare in childhood. Thymoma tumors affect both men and women equally and typically occur in individuals between their 50s and 60s. Because thymoma tumors grow slowly, the patient's survival rate is higher compared to other types of cancer.

How are thymoma tumors diagnosed?

Thymoma tumors often progress without any noticeable symptoms, and they are typically discovered incidentally during tests conducted for other medical conditions. Unless the growth in the thymus gland is significant, it may not be visible on a standard chest X-ray. Diagnosis is usually confirmed through biopsy after detecting changes in the size and shape of the thymus gland during CT, MRI, or PET/CT scans performed for other reasons. Biopsy methods include fine-needle aspiration, mediastinotomy, and VATS (video-assisted thoracoscopic surgery). VATS is the most commonly used method due to its higher accuracy compared to fine-needle aspiration biopsy.

What are the stages of thymoma tumors?

Thymoma tumors have four stages:

  1. Thymoma Stage 1: The thymoma tumor is in the first stage and is still contained within the capsule.

  2. Thymoma Stage 2: In the second stage, the thymoma tumor may have spread into the surrounding fatty tissues beyond the capsule.

  3. Thymoma Stage 3: By the third stage, the thymoma tumor may have extended beyond the capsule into the surrounding tissues, reaching the trachea, lungs, and pericardium.

  4. Thymoma Stage 4: In the fourth stage, the thymoma tumor can spread to the pleura (lung lining) and other distant organs.

What are the treatment methods of thymoma tumors?

The treatment for thymoma tumors depends on the stage at which they are diagnosed. Thymoma tumors detected in the early stages are typically treated with surgical methods alone. The lesion is removed through thoracoscopic or open surgery. In more advanced stages of thymoma tumors, chemotherapy or chemoradiotherapy may be combined with surgical treatment. Thymomas that have spread to distant organs are not operated on.


What causes thymoma tumors?

The exact causes of thymoma tumors are not yet known. Some studies have suggested that radiation therapy and early infection with the EBV virus may pose a risk for thymoma tumors, but the reasons and potential risk factors for thymoma tumors are not fully understood. Research is being conducted to clarify the relationship between thymoma and genetics.

What symptoms do thymoma tumors cause?

Thymoma tumors typically do not cause any symptoms or complaints in the majority of patients. However, about 30% to 35% of patients may present with the following symptoms:

  • Cough

  • Chest pain

  • Hoarseness

The most common paraneoplastic syndrome associated with thymoma is "myasthenia gravis." Paraneoplastic syndromes are effects caused by hormones or substances released by the tumor, not directly caused by the tumor itself. Myasthenia gravis accompanies thymoma tumors in 30% to 50% of cases.

What is myasthenia gravis?

Myasthenia gravis is a disease related to the nerve-muscle system that results in quick fatigue of voluntary muscles. The hallmark symptom is muscle weakness that worsens with exertion and improves with rest. Patients typically feel better in the mornings but experience a decline in their overall condition throughout the day. The disease can also manifest as drooping eyelids. Symptoms mainly affect the areas around the eyes, mouth, tongue, and muscles used for chewing and swallowing.

Is thymus gland cancer a deadly disease?

Untreated thymoma tumors can be fatal. However, thymoma tumors are slow-growing, so the survival rate for patients is higher compared to other types of cancer. Especially when operated on in the early stages, patients have a very long survival time.

Which department and doctor diagnose and treat thymus gland cancer?

The diagnosis and treatment of thymus gland cancer are typically carried out by chest surgery specialists in the chest surgery department of hospitals.

Is thymus gland cancer a genetic disease?

The exact cause of thymus gland cancers is not yet fully understood. However, it is believed that individuals who have received radiation therapy or have been infected with the EBV virus at an early age may have a higher risk. Research is ongoing to determine whether thymus gland tumors are genetic diseases.

Is thymus gland cancer more common in women or men?

Thymus gland cancer occurs equally in men and women.

At what ages is thymus gland cancer more commonly seen?

Thymus gland cancer, especially thymoma tumors, is extremely rare in childhood. Thymoma tumors are more commonly seen in individuals in their 50s to 60s.

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