A 41-year-old man is admitted with severe shoness of breath. He complains of a 25-lb weight loss over the last 2 mo and occasional vomiting after meals. On physical examination, vital signs are: pulse 110 bpm; temperature 98degF; respirations 24/min; blood pressure 110/70 mm Hg. Peinent findings: dullness to percussion on the left posterior chest with decreased breath sounds. A patchy area of egophony is heard over the left upper lung field posteriorly. PPD is 15 mm. CXR is shown in. The most likely diagnosis is