Question

Superior vena cava syndrome is most commonly caused by?

• A. Lymphoma
• B. Small cell lung carcinoma
• C. Non small cell lung carcinoma
• D. Secondary tumours

Hint:

Think of the central, fast-growing, mediastinal lung cancer subtype.

Answer 1

The Correct Option is B

Step 1: Superior vena cava (SVC) syndrome results from obstruction of blood flow through the SVC, producing facial and upper limb swelling, distended neck veins, dyspnoea and a plethoric face.
Step 2: The overwhelming majority of cases are caused by malignancy, and bronchogenic carcinoma is the single largest group because the right paratracheal lymph nodes and the right upper lobe lie adjacent to the SVC.
Step 3: Among lung cancers, small cell lung carcinoma (SCLC) has a strong central, mediastinal location and rapid growth, so it is the most common specific cause of SVC syndrome.
Step 4: Non small cell lung carcinoma and lymphoma (especially non-Hodgkin lymphoma) are the next most frequent causes, while metastatic or secondary tumours and benign causes such as fibrosing mediastinitis are less common.
Conclusion: The most common cause of SVC syndrome is small cell lung carcinoma, so option 2 is correct.