Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . A left chest wall Port - A - Cath is seen with catheter tip in the region of the mid SVC . Clips in the right axilla noted with absent right breast shadow in this patient with known breast cancer . There is interval development of a large right pleural effusion . In this patient with known breast cancer , a malignant effusion is of concern . Difficult to exclude underlying infection . Heart size is difficult to assess though appears grossly unchanged though silhouetting of the right heart border limits assessment . Bony structures are intact .
    OUTPUT:
    
Interval development of a large right pleural effusion , possibly malignant .