Mediastinal lymphadenopathy may manifest subtly on routine chest radiographs, particularly when arising in the left paraaortic region, where the normal pleural reflection across the aortic arch ("left paraaortic stripe") can be obscured. We report the case of an 82-year-old man with a history of renal cell carcinoma in remission who presented with fatigue, mild dyspnea, and weight loss. A postero-anterior chest X-ray revealed a double aortic contour, absent on imaging two years prior, raising the suspicion of lymphadenopathy. This prompted a non-contrast CT that identified a 2 cm paraaortic lymph node metastasis. Surgical resection was successful, though the patient later died of unrelated causes. Recognition of a double aortic contour, created by an adjacent mass displacing mediastinal fat of differing attenuation, is crucial, yet detection is often hampered by variable pleural reflections and the small size or location of nodal disease. Comparative radiographs greatly enhance diagnostic confidence. However, given that fewer than half of aortopulmonary window lymphadenopathies are visible on X-ray and false negatives are common, CT confirmation remains essential when mediastinal lymphadenopathy is suspected.