Definition and Overview

Thymoma is a tumour of the thymus gland. This is a small organ located behind the breastbone and between the lungs. It secretes a hormone called thymosin. Thymosin is important in the development of T-lymphocytes. Also called T-cells, these cells are an important part of the immune system. They help the body fight deadly pathogens.

Thymoma is a rare type of cancer. It often grows very slowly. It rarely spreads to other parts of the body. Thymomas are generally not aggressive. Thus, the prognosis for patients is often good. When caught early, it can be cured with standard cancer treatment.

Causes of Condition

The condition is often found in patients with a malfunctioning immune system. In normal circumstances, the immune system protects the body against diseases and infections. When it malfunctions, it attacks healthy cells and tissues in the body. It does so in the same way it fights pathogens.

Key Symptoms

Thymomas often do not cause symptoms in the early stages. Many early-stage cases are found accidentally when a patient undergoes a chest chest x-ray for an unrelated medical condition.

As the tumour grows, signs will begin to show. The most common is a cough that does not go away. The list also includes trouble breathing and chest pains. It is important to note that these symptoms are not specific to thymomas. This means that they can also be caused by other respiratory problems. These include asthma and lung infection. Patients with such symptoms are advised to see their doctors for diagnosis and treatment.

Who to See and Types of Treatments Available

Patients with symptoms mentioned above must undergo a number of tests to get a diagnosis. The first one is usually a physical exam where the doctor looks for signs of the condition, such as lumps in the chest area. The patient’s medical history is also reviewed. The doctor would want to know if the patient has a history of certain autoimmune diseases.

If the doctor finds any abnormality, he or she will order a chest x-ray. This test produces an image of the lung. It is a standard test used in patients with chest pains, persistent cough, and shortness of breath.

If the x-ray image shows a lump or a tumour, the doctor will order more sensitive imaging tests. These often include an MRI and PET and CT scans. These tests provide more details that a simple chest x-ray cannot provide.

The doctor will then confirm if the tumour is benign or malignant through a biopsy. This test involves getting a small piece of the tumour for further study. A biopsy can be performed during open surgery. It can also be done with the use of a fine needle to obtain a small amount of cells in the tumour.

A biopsy can determine if the tumour is cancerous or not. It can also confirm the type of cells involved and the stage of cancer.

  • Stage I - All cancer cells are contained in the thymus.

  • Stage II - Cancer cells have spread to structures surrounding the thymus gland. They may have also spread to the lining of the chest cavity.

  • Stage III - Cancer cells have spread to organs near the lungs.

  • Stage IVA - The cancer has spread around the heart and the lungs.

  • Stage IVB – The cancer has spread to the lymph system or the blood.

The standard treatment for early-stage thymoma is surgery. The conventional technique requires an incision that splits the breastbone. This allows the surgeon to access the anterior chest cavity. The surgeon will then remove the tumour and the tissue surrounding it.

Patients with small, early-stage tumours may also qualify for a less invasive type of treatment that uses small incisions and a laparoscope. This procedure minimises the many risks and complications of surgery. It is also associated with faster recovery time.

Advanced-stage thymoma is also treated with surgery. The goal is to remove as much of the tumour as possible. This can provide symptoms relief, but it does not cure the disease. Surgery is followed by radiotherapy. This treatment uses high-energy x-rays or other particles to kill remaining cancer cells in the body. It can be used alone. It can also be combined with chemotherapy. This treatment uses drugs designed to destroy cancer cells. They work by preventing cancer cells from growing and dividing. These drugs can be injected directly into a vein. They can also be taken orally.

Another treatment is called targeted therapy. It works by targeting the cancer’s specific proteins, genes, or tissue environment. It can prevent the growth and spread of cancer cells while preventing damage to healthy cells.

Each treatment method carries risks and complications. For example, surgery that removes the tumour puts the patient at risk of severe bleeding and infection. Chemotherapy, on the other hand, can cause nausea, vomiting, and hair loss. Meanwhile, the side effects of radiation therapy are fatigue, loose bowel movements, and difficulty swallowing.

These risks are carefully explained to the patient before any treatment is initiated. However, they are assured that treatments are only considered if their benefits far outweigh their risks.

Patients undergoing chemotherapy or radiotherapy are carefully monitored. They undergo imaging tests to see how their body responds to treatment. Doctors may need to make adjustments from time to time to achieve better treatment outcomes.

No cancer treatment can provide a guarantee against recurrences. It is possible for patients to develop cancer again after treatment. The cancer may develop at the original site or in other parts of the body. Thus, patients are scheduled for regular follow-ups to ensure that there are no new tumours growing inside their body. If there are, it is the doctors’ hope to catch them during the early stages so they can be easily and promptly treated.


  • Van Geffen WH, Sietsma J, Roelofs PM, Hiltermann TJ. A malignant retroperitoneal mass–a rare presentation of recurrent thymoma. BMJ Case Rep. 2011 Dec 1;2011. pii: bcr0920114737

  • Mitchell, Richard Sheppard; Kumar, Vinay; Robbins, Stanley L.; Abbas, Abul K.; Fausto, Nelson (2007). Robbins basic pathology. Saunders/Elsevier.

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