Department of Pathology, Attending Thoracic Pathologist, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA.
Mod Pathol. 2012 Jan;25 Suppl 1:S18-30. doi: 10.1038/modpathol.2011.150.
Small cell lung cancer (SCLC) comprises 14% of all lung cancers, and >30,000 new cases are diagnosed per year in the United States. SCLC is one of the most distinctive malignancies in the entire field of oncology with characteristic clinical properties, responsiveness to specific chemotherapy, genetic features and a highly reliable pathological diagnosis. SCLC is defined by light microscopy, and the most important stain is a good-quality hematoxylin and eosin (H&E)-stained section. The vast majority of cases can be diagnosed on H&E alone; however, in problem cases, immunohistochemistry can be very helpful in making the distinction from other tumors. Cytology is also a powerful tool, often being more definitive than small biopsies with scant tumor cells, crush artifact and/or necrosis. As virtually all SCLCs present in advanced stages, most patients are diagnosed based on small biopsy and cytology specimens. Historically, there has been significant evolution in the histological subclassification of SCLC dating from 1962 when Kreyberg proposed the oat cell and polygonal cell types. The current subclassification recognizes only two subtypes: pure SCLC and combined SCLC. Pathologists need to do their best to make a diagnosis of SCLC or other histological types of lung cancer and this can be achieved in most cases. This review will address some of the diagnostic problems that occur in the minority of cases and outline practical ways to address them. Brief reference will be made to other neuroendocrine lung tumors with an overview of the molecular pathogenesis of this spectrum of tumors.
小细胞肺癌（SCLC）约占所有肺癌的 14%，美国每年新诊断出的病例超过 3 万例。SCLC 是肿瘤学领域最具特征性的恶性肿瘤之一，具有独特的临床特征、对特定化疗药物的敏感性、遗传特征和高度可靠的病理诊断。SCLC 通过光学显微镜定义，最重要的染色是高质量的苏木精和伊红（H&E）染色切片。绝大多数病例仅凭 H&E 染色即可诊断；然而，在疑难病例中，免疫组织化学在区分其他肿瘤方面非常有帮助。细胞学也是一种强大的工具，通常比含有少量肿瘤细胞、压碎伪影和/或坏死的小活检更具确定性。由于几乎所有 SCLC 都处于晚期阶段，因此大多数患者都是根据小活检和细胞学标本诊断的。从 1962 年 Kreyberg 提出燕麦细胞和多边形细胞类型以来，SCLC 的组织学分类发生了重大演变。目前的分类仅承认两种亚型：纯 SCLC 和混合型 SCLC。病理学家需要尽最大努力做出 SCLC 或其他类型肺癌的诊断，在大多数情况下都可以实现这一目标。本综述将讨论少数病例中出现的一些诊断问题，并概述解决这些问题的实用方法。简要提及其他神经内分泌肺肿瘤，并概述该肿瘤谱的分子发病机制。
