Small peripheral lung adenocarcinoma: clinicopathological features and surgical treatment.

The clinical use of high-resolution computed tomography (CT) has greatly advanced diagnosis of small peripheral lesions of the lung. In CT images, these lesions often exhibit ground-glass opacity (GGO). Ground-glass opacity is typical of noninvasive bronchioloalveolar carcinoma (BAC), which is characterized by a lepidic pattern of cells that line the alveoli but do not invade neighboring structures. Bronchioloalveolar carcinoma is classified as a subset of lung adenocarcinoma, but has distinct clinical and pathological features and a favorable prognosis. Most small peripheral lung lesions, including BAC, probably originate in the epithelium of the peripheral airway. As with other subsets of non-small cell lung cancer, surgical resection is a potentially curative treatment. However, it is questionable whether a lobectomy is necessary for small lesions that exhibit GGO, particularly when they are <1 cm in diameter. Although several Japanese investigators have suggested that a limited resection, including a wedge resection and a segmentectomy without nodal dissection, is an appropriate treatment for small lung adenocarcinomas, this approach should be validated by clinical trials.