You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is The most common cause of SVC syndrome is ? and explain in detail?
Ans. is 'b' i.e., Extrinsic compression Superior venacava syndrome o 'Superior vena caval syndrome' or 'SVCS' is the clinical manifeststion of superior vena cava obstruction with severe reduction in venous return from head, neck and upper extremities. Most common cause (90%) appears to be extrinsic compression from malignant tumors such as Lung cancer, Lymphoma, and Metastatic tumors. of the malignant tumors, most common tumors is Lung cancer or Bronchogenic Carcinoma, especially small cell Ca o In young adults, malignant lymphoma is the leading cause of SVCS. o Non-malignant causes of SVCS are include benign tumors, aoic aneurysm, thyromegaly, thrombosis and fibrosing mediastinitis from prior irradiation or histoplosmosis.