The superior vena cava syndrome (SVCS) is considered an emergency and requires immediate treatment; therefore, the etiologic diagnosis is essential before deciding on its implementation. The management of SVCS consists on the relief of symptoms and treatment of the underlying disease, aiming to restore the blood flow. We present a 5 years old boy with a history of B-cell ALL. His oncologic state was that of complete remission. In February 2013 he consulted for respiratory distress syndrome (RDS) of rapid evolution, and facial edema which progressed within 24 hours. CT chest and neck angiography was performed, showing pseudo nodular tissue compressing the SVC. Emergency endocavitary biopsy reported diffuse lymphoproliferative infiltration Chemotherapy is administered, with good results and hospital discharge. The SVCS is an oncologic emergency that requires prompt diagnosis and immediate treatment in order to improve results.