Thymic Malignancies

Diagnosis

The diagnosis of thymus cancer may be made through the following methods:

• Medical history and physical examination: Most patients with thymus cancer consult primary care physicians when the symptoms start interfering with their daily activities. The patients are asked about the development of the symptoms, severity, and progression to determine the rate of disease progression. The patients are also asked about their medical history. Thymus cancer is usually suspected if the patients have signs and symptoms related to red cell aplasia, hypogammaglobulinemia, or myasthenia gravis. Further, the oncologists consider advanced age and ethnicity while suspecting the presence of thymus cancer, as thymus cancer mostly occurs in patients during their 70s. Chest X-ray: It is the primary imaging modality recommended in patients experiencing chest-related symptoms. The X-ray is taken posterior-anterior and laterally to detect the mass in the middle of the chest. A main hallmark of thymus cancer revealed during radiographic examination is the pleural metastases.
• CT scan: CT is one of the preferred imaging techniques for diagnosing thymoma. The CT scan may also involve the use of a contrast agent. The contrast dye is injected into the vessels. CT scan with contrast imaging results in more detailed and clear tumor images. Sometimes, a CT scan is the only imaging modality required for diagnosing thymic carcinoma or thymoma. It is also helpful in detecting invasive diseases. The images obtained through the CT scan are also used to determine the spread of thymus tumor to the diaphragm or surrounding structures and other organs, such as bones, kidneys, liver, and brain. It differentiates between the pleural involvement with local chest wall invasion and mesothelioma.
• MRI: Magnetic resonance imaging provides detailed images of the tumor using strong magnets and radio waves. The clarity of images helps in differentiating thymus cancer and other potential benign growths. However, it also helps in differentiating thymic carcinoma or thymoma.
• PET scan: PET scan is the test performed to detect the cancer cells in all body organs. It is a known fact that rapidly dividing cells require more energy sources. This principle determines the spread of thymus cancer to other organs. During this procedure, radioactive sugar derivatives are injected through the vessels. The radioactive sugar solution accumulates near the rapidly dividing cells that can be visualized through a special camera. Some PET scans also use contrast media to create more clear images.
• Blood tests: Blood tests are unable to detect the presence of thymus cancer. However, they are recommended in the patients to determine the presence of antibodies for myasthenia gravis or other autoimmune disorders. Blood tests are also performed in patients undergoing chemotherapy or surgery for treating thymus cancer.
• Biopsy: In the case of a thymic tumor, a biopsy is required to confirm the presence of a thymic tumor, even when signs, symptoms, and results of imaging tests strongly suspect the disease. A biopsy is a procedure that involves the removal of the samples of abnormal tissues and sending them to the laboratory for analysis. However, a biopsy is not usually performed in case of a thymoma, as imaging tests are sufficient in most cases to confirm the presence of a thymoma. Thus, the complete thymoma tumor is removed during biopsy rather than removing a small sample.