An 11-year-old boy presents to his pediatrician. He has been experiencing fatigue, persistent cough with wheezing, dyspnea, and loss of appetite for the last month. Findings on physical exam show nothing remarkable; his heart rhythm is normal, he has slight wheezing on auscultation, and there is no lymphadenopathy. The patient appears pale and tired.

CT reveals a 3-cm ground-glass opacity with a small, central-solid component in the upper left lobe. There is no evidence of lymphatic, vascular, or pleural invasion and no tumor necrosis. Laboratory findings were all within the normal range for complete blood cell counts and liver and kidney function, as well as for the biomarkers carcinoembryonic antigen, alpha fetoprotein, carbohydrate antigen 19-9, carbohydrate antigen 72-4, cytokeratin 19 fragment, neuron-specific enolase, and serum ferritin. Ultrasonography of the liver, spleen, pancreas, and gallbladder were negative, as was brain MRI.