Bronchioloalveolar carcinoma (BAC) is a subtype of non-small cell lung cancer (NSCLC) with distinct clinical and pathologic features. Although BAC appears to be on a pathologic continuum with adenocarcinoma, the most recent World Health Organization (WHO) classification system has set stringent criteria for the diagnosis. Though malignant, these cancers tend to be peripheral and grow in a lepedic fashion along the alveolar septae without parenchymal invasion. This clear distinction based on histopathology allows for a more definite separation of the natural history and behavior of BAC in clinical studies. Recent clinical trials of molecular targeted anticancer therapies have led to a deeper understanding of the unique features of this cancer and suggest that BAC may require a different therapeutic paradigm from other NSCLCs.

中文翻译：

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重新定义支气管肺泡癌。

支气管肺泡癌（BAC）是非小细胞肺癌（NSCLC）的一种亚型，具有独特的临床和病理特征。尽管BAC似乎是腺癌的病理连续体，但最新的世界卫生组织（WHO）分类系统已为诊断设定了严格的标准。尽管是恶性的，但这些癌症往往是边缘性的，并沿肺泡隔以麻风状生长，而没有实质侵袭。基于组织病理学的这种明显区别允许在临床研究中更明确地分离BAC的自然史和行为。分子靶向抗癌疗法的最新临床试验使人们对该癌症的独特特征有了更深入的了解，并表明BAC可能需要与其他NSCLC不同的治疗范例。