History and Physical Examination
Of patients with a thymoma, one third to one half are asymptomatic, and one third present with local symptoms related to the tumor's encroachment on surrounding structures. These patients may present with cough, chest pain, superior vena cava (SVC) syndrome, dysphagia, and hoarseness if the recurrent laryngeal nerve is involved. One third of cases are found incidentally on radiographic examinations during a workup for myasthenia gravis (MG).
Although development of a thymoma in childhood is rare, children are more likely than adults to have symptoms. Several explanations for the prevalence of symptoms in children have been proposed, including the following:
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Children are more likely to have malignancy
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Lesions are more likely to cause symptoms by compression or invasion in the smaller thoracic cavity of a child
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The most common location for mediastinal tumors in children is near the trachea, resulting in respiratory symptoms
Four cases of patients who presented with severe chest pain secondary to infarction or hemorrhage of the tumor have been reported. Cases of invasion into the SVC resulting in venous obstruction have also been reported. [4] The clinician should be aware of these rare presentations of a thymoma.
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Anatomy of thymus, with emphasis on blood supply and relation to recurrent laryngeal and phrenic nerves.
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Lateral view of thymus. Thymic arteries are derived from adjacent internal mammary arteries; inferior thymic vein empties into innominate vein. Thymus gland's surrounding vascular and neural structures may be invaded during spread of thymoma.
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CT scan clearly illustrates mass in right anterolateral mediastinum.
Tables
Stage |
5-Year Survival |
10-Year Survival |
I |
90% |
80% |
II |
90% |
80% |
III |
60% |
30% |
IV |
Less than 25% |
N/A |
Type |
Histologic Description |
Disease-Free Survival at 10 years,* % |
A |
Medullary thymoma |
100 |
AB |
Mixed thymoma |
100 |
B1 |
Predominantly cortical thymoma |
83 |
B2 |
Cortical thymoma |
83 |
B3 |
Well-differentiated thymic carcinoma |
35 |
C |
Thymic carcinoma |
28 |
*Series of 100 thymomas resected in Japan between 1973 and 2001 using WHO classification. [6] |
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Stage |
Definition |
Treatment |
I |
Encapsulated tumor with no gross or microscopic invasion |
Complete surgical excision |
II |
Macroscopic invasion into the mediastinal fat or pleura or microscopic invasion into the capsule |
Complete surgical excision and postoperative radiotherapy to decrease the incidence of local recurrence |
III |
Invasion of the pericardium, great vessels, or lung |
Complete surgical excision and postoperative radiotherapy to decrease the incidence of local recurrence |
IVA |
Pleural or pericardial metastatic spread |
Surgical debulking, radiotherapy, and chemotherapy |
IVB |
Pleural or pericardial metastatic spread |
Surgical debulking, radiotherapy, and chemotherapy |
