History
One third of patients with thymoma present with local symptoms. An additional one third of patients with thymoma are asymptomatic and are diagnosed as the result of abnormality on a chest radiograph (eg, mediastinal widening on posteroanterior [PA] views, retrosternal opacification on lateral views). Thirty percent of patients present with myasthenia gravis (MG). [1]
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Structural problems, such as compression syndromes that involve the bronchi or lungs or superior vena cava syndrome (SVCS), can occur from local spread of benign thymoma, thymic cysts, or thymic carcinoma.
Presenting symptoms may include chest pain, SVCS, dyspnea, dysphagia, and cough.
Areas of benign thymoma can become highly vascular or necrotic and lead to bleeding.
Noninvasive large thymomas can be present for extended periods without symptoms. Takanami et al (1999) described a patient with a noninvasive thymoma that was present and asymptomatic for 21 years prior to the development of a compression syndrome. [21]
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Clinical manifestations include paraneoplastic syndromes and immunodeficiency. Approximately 70% of patients with thymoma are symptomatic for other illnesses, including MG (50%), hypogammaglobulinemia (5%), pure red blood aplasia (5%), and one or more of the immune or endocrinologic diseases (10%).
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Patients with Good syndrome present with recurrent bacterial, viral, and fungal infections. Recurrent upper and lower respiratory tract infections with encapsulated and atypical bacteria are also reported. In addition, opportunistic infections, including mucocutaneous candidiasis, recurrent herpes simplex virus, varicella-zoster virus, cytomegalovirus, and Pneumocystis carinii pneumonia have also been reported. Chronic diarrhea without clear etiology may also be present. [22]
Physical
One third of patients with thymoma present with local symptoms (eg, chest pain, SVCS, dyspnea, dysphagia, cough). An additional one third of patients with thymoma are diagnosed as the result of abnormality on a chest radiograph, such as mediastinal widening on PA views or retrosternal opacification on lateral views.
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Consider imaging studies to exclude thymoma in individuals with paraneoplastic syndromes (eg, pemphigus, common variable immunodeficiency [CVID], red cell aplasia) or in those with a compression syndrome.
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Observe patients with acquired hypogammaglobulinemia at regular intervals for the development of thymoma. [11]
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Inversely, if thymoma is present, consider appropriate laboratory studies to screen for these disorders (see Laboratory Studies).
Tables
Clinicopathologic Classification |
WHO Type |
Terminology of the Histogenetic Classification for the Histologic Subtypes of Thymic Epithelial Tumors |
Benign thymoma |
A AB |
Medullary thymoma Mixed thymoma |
Malignant thymomas, Category I |
B1 B2 B3 |
Predominantly cortical thymoma Cortical thymoma Well-differentiated thymic carcinoma |
Malignant thymomas, Category II |
C |
Epidermoid keratinizing (squamous cell) carcinoma Epidermoid nonkeratinizing carcinoma Lymphoepithelioma-like carcinoma Sarcomatoid carcinoma (carcinosarcoma) Clear cell carcinoma Mucoepidermoid carcinoma Undifferentiated carcinoma |
Cisplatin |
75 mg/m2 on day 1 |
3 courses repeated q3wk |
Epirubicin |
100 mg/m2 on day 1 |
|
Etoposide |
120 mg/m2 on days 1, 3, and 5 |
|
Surgery and radiation in patients with complete or partial response to chemotherapy |
4500 cGy if complete resection 6000 cGy if incomplete resection |
|
Cisplatin |
50 mg/m2 |
2-4 cycles q3wk |
Doxorubicin |
50 mg/m2 |
|
Cyclophosphamide |
500 mg/m2 |
|
Followed by radiation |
54 Gy to the primary tumor and lymph nodes |
|
Cisplatin |
75-100 mg/m2 on day 1 |
Repeated q3wk 3 times before surgery and 2 or 3 times after surgery |
Epirubicin hydrochloride |
100 mg/m2 on day 1 |
|
Etoposide |
120 mg/m2 on days 1, 3, and 5 |
|
Postoperative radiation in patients with radical resection |
30 Gy |
Delivered in 3 wk with 5 fractions per wk |
Postoperative radiation in patients with incomplete resection |
50 Gy |
Delivered in 5 wk with 5 fractions per wk |
Octreotide |
1.5 mg/d SC |
In patients shown to have somatostatin receptors |
Lanreotide |
30 mg/d SC q14d |
Switch to this longer-acting somatostatin analogue or depot form of octreotide if short-acting octreotide is well tolerated |
Prednisone |
0.6 mg/kg/d PO for 3 mo, then decreasing to 0.2 mg/kg |
|
