An 80-year-old man with surgical history of colon cancer was referred to our department for surgical treatment for multiple metastatic lung tumors in the left upper lobe. The patient had been showing complete atelectasis of the left lower lung lobe one year prior to the consultation. Six months after wedge resections for the pulmonary metastases, the left lower lobe was re-expanded, showing bronchiectasis with rudimentary pulmonary artery branches. Further, the ventilation-perfusion scintigraphy showed decreased uptake in the left lower lobe. These findings indicated that the patient had the hypoplasia of the left lower lobe.