In recent years, the clinical use of high-resolution computed tomography has greatly advanced the diagnosis of small lesions of the peripheral lung. Such small lesions are often associated with ground-glass opacity in computed tomography findings. The noninvasive bronchioloalveolar carcinoma component with a replacement growth pattern of alveolar lining cells manifests as ground-glass opacity. Bronchioloalveolar carcinoma is classified as a subset of lung adenocarcinoma, but has a distinct clinical presentation, tumor biology, and favorable prognosis. Most small peripheral lung lesions including bronchioloalveolar carcinoma putatively originate from the peripheral airway epithelium, in which the epidermal growth factor receptor gene is frequently mutated. As with other subsets of non-small cell lung cancer, surgical resection is a potentially curative treatment. For the ground-glass opacity type of tiny lesions, particularly those less than 1 cm in their greatest dimension, the question has been raised whether lobectomy is really needed. Although several authors in Japan suggest the suitability of limited resection including segmentectomy and wedge resection without any nodal dissections for these small lung adenocarcinomas, this procedure should be validated in future clinical trials.