Definition
The thymoma is a rare potentially malignant tumor of the thymus (a small organ located behind the sternum, in the anterior mediastinum, belonging to the lymphatic system).
The thymoma derives, in particular, from the transformation in the neoplastic sense of the epithelium that covers the gland.
The causes of thymoma are not yet known. Usually, the pathology begins between 30 and 70 years of age, but occasionally can occur during childhood.
Most common symptoms and signs *
- Asthenia
- Dysphagia
- Dyspnoea
- Chest pain
- Muscle pains
- Edema
- Temperature
- Muscular hypotrophy
- Pancytopenia
- Weight loss
- Cold
- Sense of suffocation
- Cough
Further indications
The thymoma can be found with some frequency in people with myasthenia gravis or other autoimmune diseases (such as rheumatoid arthritis and systemic lupus erythematosus). This tumor can also manifest itself in association with haematological disorders, hypertension, diabetes mellitus, renal failure, coronary artery disease and other neoplastic diseases.
In about half of the cases, the thymoma is asymptomatic and the finding is purely coincidental (the mediastinal mass can be identified, for example, during radiological examinations performed for other purposes). The remaining part of the patients presents, instead, thoracic symptoms, such as respiratory difficulty, persistent cough, chest pain, fatigue and pneumonia. In addition, upper airway infections, muscle weakness, dysphagia (due to esophageal compression) and weight loss are possible.
Prognosis depends on the stage of the thymoma at the time of diagnosis and the type of treatment. Generally, the tumor grows slowly, spreading in rare cases outside the thymus itself. However, some thymomas are more aggressive and can extend to the surrounding tissues and organs (lungs and pleura) or give rise to metastases to the peritoneum, bones, central nervous system or liver.
The diagnosis of thymoma is based on the clinical picture, chest radiograph and pathological examination of surgically removed tissues. In addition, other investigations such as computerized axial tomography, angiography and magnetic resonance imaging may be useful to assess the extent of the lesions.
In the initial stages of the thymoma, the treatment consists in the complete excision of the neoplastic mass (thymectomy), usually performed by means of a median sternotomy. In advanced stages, however, surgery is associated with adjuvant therapy, such as radiotherapy or chemotherapy.
