<prompt> A 53 years old patient was admitted complains of dyspnea. On examination he has face with engorged veins over the chest. SVC obstruction is suspected. Chest x-ray shows mediastinal enlargement. What is the next step?Total blood count with peripheral smearCT thoraxSta cyclophosphamideUrgent referral to  <response>: SUPERIOR VENA CAVA SVC SYNDROME Clinical manifestation of SVC obstruction, with severe reduction in venous return from head, neck and upper extremities. MC cause is Lung cancer small cell squamous cell carcinomaQ, along with lymphoma and metastatic tumors responsible for more than 90 of all SVC syndrome. In young adults, malignant lymphoma is the leading cause of SVC syndromeQ. CLINICAL FEATURES Patients present with neck facial swelling especially around the eyes, dyspnoea coughQ. DIAGNOSIS Most significant chest radiographic finding is widening of the superior mediastinum MC right sideQ CT scan: Investigation of choiceQ. TREATMENT Potentially life threatening complication of superior mediastinal mass is tracheal obstructionQ. Diuretics with low salt diet, head elevation and oxygen may produce temporary symptomatic relief. Treatment Underlying cause Radiation TherapyQ Non-small cell lung cancer, Metastatic solid tumors ChemotherapyQ Small cell carcinoma or lymphoma SurgeryQ All other cases 