Thymic tumors pt.1 Flashcards
Thymoma and age
Peak incidence between ages 40 to 60 years
Thymoma and sex
Equal
What percentage of mediastinal neoplams do thymomas make up
About 20 percent of mediastinal neoplasms
Annual incidence of thymoma
1-3 million cases per year
Risk factors for thymoma
There are no known risk factors, and there is a strong association with myasthenia gravis (30-50% of cases) and other paraneoplastic syndromes
Staging system used for thymoma
- AJCC TNM staging system/ TNM (IASLC (International Association for the Study of Lung Cancer) / ITMIG ( International Thymic Malignancy Interest Group), basically the same
- Masaoka staging
- WHO staging
- Bergh and Wilkins and Castleman
Tumor description based on AJCC TNM staging system
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor encapsulated or extending into the mediastinal fat; may involve the mediastinal pleura
T1a Tumor with no mediastinal pleura involvement
T1b Tumor with direct invasion of mediastinal pleura
T2 Tumor with direct invasion of the pericardium (either partial or full thickness)
T3 Tumor with direct invasion into any of the following: Lung, brachiocephalic vein, superior vena cava, phrenic nerve, chest wall, or hilar (extrapericardial) pulmonary artery or veins
T4 Tumor with invasion into any of the following: Aorta (ascending, arch, or descending), arch vessels, intrapericardial pulmonary artery (main pulmonary artery), myocardium, trachea, esophagus
Node description based on AJCC TNM staging system
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in anterior (perithymic) lymph nodes
N2 Metastasis in deep intrathoracic or cervical lymph nodes
Metastasis description based on AJCC TNM staging system
M0 No pleural, pericardial, or distant metastasis
M1 Pleural, pericardial, or distant metastasis
M1a Separate pleural or pericardial nodule(s)
M1b Pulmonary intraparenchymal nodule or distant organ metastasis
Clinical stage for thymoma based on TNM
T1 a,b N0 M0 I
T2 N0 M0 II
T3 N0 M0 IIIA
T4 N0 M0 IIIB
Any T N1 M0 IVA
Any T N0, N1 M1a IVA
Any T N2 M0, M1a IVB
Any T Any N M1b IVB
Masaoka staging
Stage I: Macroscopically completely encapsulated and microscopically no capsular invasion
Stage II: Macroscopic invasion into surrounding fatty tissue or mediastinal pleura, or microscopic invasion into capsule
Stage III: Macroscopic invasion into neighboring organs (ie, pericardium, great vessels, or lung)
Stage IVa: Pleural or pericardial dissemination
Stage IVb: Lymphogenous or hematogenous metastasis
WHO staging of thymomas and their frequency
Thymomas are subdivided into different types based on the morphology of epithelial tumor cells, the proportion of the non-tumoral lymphocytic component and resemblance to normal architecture:
- Type A
- Type AB
- Type B1
- Type B2
- Type B3
- Thymic carcinoma (Type C thymoma)
- Type AB and B2 are most common (about 25% each), other ones represent each about 15% of cases, Type A least common with 12%
Mortality rate for thymoma
10 year survival rate:
- 95% for stage 1
- 90% for stage 2
- 70% for stage 3
- 55% for stage 4a
- 40% for stage 4b
Diseases associated with thymoma
- MIASTENIA GRAVIS
- MEDULLARY APLASIA AND HEMATOLOGICAL DISEASES
- AGAMMAGLOBULINEMIA
- CUSHING SYNDROME AND ENDOCRINOLOGICAL DISORDERS
- NEUROMUSCULAR DISEASES
- IMMUNODEFICIENCY SYNDROME
- COLLAGEN AND BONE PATHOLOGIES
- NEFROPATHY
- DERMATOLOGIC DISEASES
Therapeutic approaches for thymoma
- SURGERY (First choice when it is possible, considered essential in the
treatment of thymoma even for advanced disease) - Advanced thymoma with great vessel, pleural or pericardial invasion
is difficult to manage by surgery alone. - ADJUVANT THERAPY (Especially Radiotherapy)
- INDUCTION THERAPY (Chemo and Radiotherapy) FOLLOWED BY SURGERY
- Neoadjuvant chemotherapy is effective in advanced stage
