Cardiothoracic Surgery: Mediastinal Tumors
Mediastinal Tumors
Most Common Mediastinal Tumors
- Pediatrics: Neurogenic Tumors (Posterior Mediastinum)
- Most Common in Anterior/Middle Mediastinum: Lymphoma
- *Previously Considered the Most Common Mediastinal Tumor Overall
- Adults: Thymoma
- Most Common Mediastinal Tumor Overall
Malignancy Risk
- Asymptomatic: 90% are Benign
- Symptomatic: 50% are Benign
Mediastinal Mass Lesions
Anterior Mediastinal Tumors Mn
- Thymus
- Thymoma – Most Common Anterior Mediastinal Mass
- Thymic Hyperplasia
- Thymic Carcinoma
- Thymic Cyst
- Thyroid
- Substernal Goiter
- Thyroid Carcinoma
- Ectopic Thyroid Tissue
- Teratoma & Other Germ Cell Tumors
- Teratoma – Most Common Benign Germ Cell Tumor
- Seminoma – Most Common Malignant Germ Cell Tumor
- Non-Seminoma
- Ectopic Parathyroid Adenoma
- Lymphoma
- Lipoma & Liposarcoma
- Fibroma & Fibrosarcoma
- Descending Necrotizing Mediastinitis
- Vascular Aneurysm
Middle Mediastinal Tumors
- Lymphadenopathy – Most Common Middle Mediastinal Mass
- Lymphoma – Most Common Cause of Mediastinal Lymphadenopathy
- Metastatic Lung Cancer
- Cardiac Tumors
- Myxoma – Most Common Benign Cardiac Tumor
- Angiosarcoma – Most Common Malignant Cardiac Tumor
- Lung Cancer – Most Common Metastatic Source
- Cardiovascular Aneurysm
- Pericardial Cysts
- Pericardial Cancer
Posterior Mediastinal Tumors
- Neurogenic Tumors – Most Common Posterior Mediastinal Mass
- Intercostal Nerves
- Neurilemoma (Schwannoma) – Most Common Neurogenic Tumor
- Neurofibroma & Neurofibrosarcoma
- Neurosarcoma
- Sympathetic Ganglia
- Ganglioma
- Ganglioneuroblastoma
- Neuroblastoma
- Paraganglia Cells
- Paraganglioma
- Intercostal Nerves
- Esophageal Tumors
- Esophageal Cancer
- Esophageal/Enteric Cysts
- Esophageal Diverticula
- Hiatal Hernia
- Esophageal Varices
- Bronchogenic Cysts – Most Common Mediastinal Cyst (60%)
- Lymphoma
- Descending Necrotizing Mediastinitis
Thymoma
Basics
- Definition: Tumor of the Thymus
- Rare in Pediatrics
- 30-60% are Invasive/Malignant
- Rare Distant Metastases (< 5%)
- 30-50% are Associated with Myasthenia Gravis
Presentation
- 50% are Asymptomatic & Found Incidentally
- Chest Pain
- Compressive Symptoms:
- Shortness of Breath
- Cough
- Phrenic Nerve Palsy
- Superior Vena Cava Syndrome
- Pleural Effusion
- Pericardial Effusion
Masaoka Stage
- Stage I: Encapsulated with No Invasion Through the Thymic Capsule
- Stage II: Invasion Through the Thymic Capsule
- IIa: Microscopic Invasion
- IIb: Macroscopic Invasion
- Stage III: Invasion of Neighboring Structures (Pericardium, Great Vessels, Lung)
- Stage IV:
- IVa: Pleural or Pericardial Dissemination
- IVb: Lymphogenous or Hematogenous Metastasis
Diagnosis
- Initial Evaluation: Imaging (CT/MRI)
- Tissue Diagnosis Required for Definitive Diagnosis:
- Resectable: Surgical Resection
- Unresectable: Core Needle Biopsy
Treatment
- Primary Treatment: Total Thymectomy & En Bloc Resection
- Resect Regardless of Symptoms
- Resect All Thymic-Appearing Tissue Anterior to the Pericardium (Thymus is Visually Indistinguishable from Mediastinal Adipose Tissue)
- Borders of Resection:
- Lateral: Phrenic Nerves
- Superior: Innominate Vein
- Inferior: Diaphragm
- Stage III: Neoadjuvant Chemotherapy, Total Thymectomy & Adjuvant Radiation Therapy
- Risk for Myasthenic Crisis Postoperatively
Mnemonics
Anterior Mediastinal Tumors
- an-T-erior T’s – Most Start with “T”