Mediastinal tumors - Thymoma

What is it?

Thymic tumors account for less than 1% of all cancers and are therefore considered rare cancers with an incidence of about 0.15 cases per 100,000 people. The incidence is higher over age 65 with no significant differences between men and women. 

The thymus is an organ located in the space enclosed anteriorly by the sternum, posteriorly by the heart and large vessels, and laterally by the two lungs. It plays an important role within the lymphatic system in the development of certain lymphocytes.

Thymic neoplasms are divided into: 

  • thymoma: a tumor that arises from the epithelial cells lining the thymus. It arises in adulthood, over the age of 40. Thymoma may be associated with other immune-related diseases such as myasthenia gravis. Typically this tumor is localized to the thymus with a fairly indolent evolution; over time however it can become more invasive involving the pleura and lungs. Rarely, pleural and lymph node metastases can also be found;
  • thymic carcinoma: accounts for about 5-10% of thymic tumors. It originates from the cells of the thymus lining epithelium, but has significantly greater invasiveness characteristics. It grows rapidly and frequently tends to spread to other locations;
  • thymic carcinoid: almost never presents with symptoms associated with other diseases such as myasthenia gravis. Thymic carcinoid is a particularly rare tumor of neuroendocrine origin. It affects men more frequently and, compared with thymoma, has a greater tendency to spread to other sites or recur. Thymic carcinoids may be associated with multiple endocrine neoplasia syndrome type 1 (MEN-1), which is a rare genetic disease.

Which are the symptoms?

About 30-40% of patients with thymoma are asymptomatic. The most frequently observed symptoms may be: 

  • chest pain;
  • persistent cough;
  • breathlessness or dyspnea.

Very often the symptoms may instead be related to myasthenia gravis, a condition often associated with the presence of a thymoma. Myasthenia gravis is an autoimmune disease characterized by the presence of antibodies directed against the neuromuscular plaque and especially at the acetylcholine receptor. The presence of antibodies directed against the neuromuscular plaque inhibits the effect of acetylcholine resulting in muscle weakness. In these cases, the symptoms may be: 

  • difficulty keeping the eyes open (eyelid ptosis);
  • fatigue (asthenia);
  • double vision or diplopia,
  • difficulty swallowing;
  • respiratory failure.

How is it diagnosed?

The diagnostic tests used for thymic neoplasms are: 

  • chest X-ray; 
  • CT (computed tomography) scan: this is the most commonly used test because it can determine the extent of the disease and the characteristics of the thymic nodule. On CT scan, the disease presents as an oval or roundish mass within the thymus; 
  • MRI (nuclear magnetic resonance imaging): allows to characterize with greater definition the features of the thymic mass and assess the infiltration of the neoplastic mass to the surrounding organs;
  • PET (positron emission tomography) scan: allows for metabolic characterization of the tumor; 
  • thymus biopsy: it can be performed thoracoscopically or, more frequently, CT-guided. It is reserved for larger neoplastic forms, when they therefore require preoperative oncologic treatment;
  • antibody assay (anti acetylcholine receptor or anti muscarinic receptor): it allows for assessment of the presence of myasthenia gravis associated with thymoma.

Suggested exams

How is it treated?

Treatments of thymic neoplasms include: 

  • surgery: represents the gold standard of treatment for thymic neoplasms and is often the only treatment required for patients diagnosed at an early stage (stage I and II). Very often surgery is possible through minimally invasive access (videothoracoscopy, or robotic surgery). Its use allows for rapid postoperative recovery, improved quality of life, and a low rate of surgery-related complications;
  • radiation therapy: sometimes used after surgery (adjuvant therapy) to prevent disease recurrence, especially in cases where the disease is extracapsular;
  • chemotherapy: chemotherapy treatment involves the use of cisplatin as the drug of first choice combined with etoposide.

Suggested procedures

Where do we treat it?

Within the San Donato Group, you can find Mediastinal tumors - Thymoma specialists at these departments:

Are you interested in receiving the treatment?

Contact us and we will take care of you.