Thanks to Albert and Geoff for presenting an extremely compelling case of a young woman with 3 weeks of dyspnea on exertion found to have a large anterior mediastinal mass compressing her great vessels and a large pericardial effusion.
The incredible Sarah Schaeffer wrote amazing pearls the anterior mediastinal mass ddx that I’ll re-post here
The differential depends on whether the mass is in the anterior, middle, or posterior mediastinum
Anterior Mediastinal Mass – the terrible Ts + others
- Thymus – thymoma, cyst, hyperplasia, carcinoma
- (Terrible) Lymphoma
- Germ Cell Tumor – Teratoma, seminoma, non-seminomatous GCT (choriocarcinoma, etc)
- Intrathoracic Thyroid – substernal goiter, ectopic thyroid
- Others: Parathyroid adenoma, hemangioma, lipoma, liposarcoma, fibroma, fibrosarcoma, Foramen of Morgagni (diaphgragm) hernia
Middle Mediastinal Mass
- Bronchogenic cyst
- Pericardial cyst
- Lymphadenopathy – lymphoma, sarcoid, metastatic lung CA, etc
- Enteric cyst
- Esophageal tumors
- Vascular masses and enlargement
Posterior Mediastinal Mass
- Neurogenic tumors – neurofibroma, neurolemona, neurosarcoma, ganglioneuroma, ganglioneuroblastoma, neuroblastoma, chemodectoma, pheochromocytoma (among the 10% extra-adrenal)
- Thoracic spine lesions
Some additional nuggets
- Most Anterior mediastinal masses are malignant – 60% in one case series. Thymoma is the most common.
- In women hodgkins disease incidence peaks in the third decade of life. Based on this patient’s symptoms
Tissue is the issue
- Oncologists have drilled into us that tissue is critical. In anterior mediastinal masses, distinguishing between thymoma and lymphoma can be tricky
- In general options for biopsy are percutaneous (CT guided), Endobronchial (if abutting the airway), and surgical (via mediastinoscopy or open resection).
- Geoff taught us that if a thymoma capsule ruptures during biopsy, it can seed the mediastinum or, more catastrophically, the pleura. Pleural seeing makes a previously curable disease potentially incurable.
- at times, if a mass looks very thymoma-like, surgeons will proceed directly to open resection. The big downside of this is that if the disease is lymphoma, resection is not the appropriate treatment.
What on earth is mediastinoscopy? A surgical procedure. See below