What are the classic signs of superior vena cava syndrome (SVCS)?

The classic signs of superior vena cava syndrome (SVCS) are facial edema, dyspnea, and edematous arms, which are all indicators of impaired venous return through the superior vena cava. This condition often occurs due to obstruction in the superior vena cava, commonly caused by malignancies such as lung cancer or lymphadenopathy pressing on the vein.

Facial edema is noticeable as it develops due to increased pressures in the venous system and can lead to a characteristic "puffy" appearance in the face. Dyspnea, or difficulty breathing, can result from the accumulation of fluid and pressure in the thoracic cavity, affecting lung function and leading to shortness of breath. The edematous arms are also due to increased venous pressure and blood pooling, which can be a direct consequence of the obstruction in the superior vena cava.

This combination of symptoms is quintessentially associated with SVCS, making this answer a comprehensive reflection of the syndrome's clinical presentation. The other options do not encapsulate the hallmark symptoms of this condition accurately.