Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
Cancer Cytopathol. 2013 Nov;121(11):629-37. doi: 10.1002/cncy.21314. Epub 2013 Aug 13.
The significance of histologic subtyping of surgically resected lung adenocarcinoma (ADC) was recently proposed by the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification. Approximately 70% of lung cancer patients present with advanced disease, and small biopsies or cytology specimens are frequently the only available diagnostic material. It is uncertain whether proposed morphologic subtyping of ADC can be applied to small specimens. The objective of this study was to assess the applicability of morphologic subtyping of ADC on cytologic specimens.
Consecutive, newly diagnosed primary lung ADC specimens from patients with matched surgical resection and cytology specimens (n = 66) were selected for the study. The dominant morphologic pattern was determined according to the IASLC/ATS/ERS classification. The number and percentage of malignant cells in cytology specimens were also evaluated.
Concordant subtyping of ADC between the dominant pattern on resection and cytology specimens was observed in 26 cases (40%), and was discordant in 32 cases (48%). Concordance increased in specimens that had >200 cells and when correlating with the primary or secondary histologic pattern. The acinar pattern was the most common in concordant cases, whereas discordant cases had a predominantly solid pattern.
Application of the IASLC/ATS/ERS ADC classification to cytologic specimens is challenging and depends on the sufficient cellularity of cytologic preparations. The identification of solid and micropapillary patterns is prognostically important but may be unreliable and difficult on cytology specimens. Future studies are needed to establish reproducible cytologic criteria for the precise subtyping of lung ADC on small specimens.
国际肺癌研究协会/美国胸科学会/欧洲呼吸学会（IASLC/ATS/ERS）分类最近提出了对手术切除肺腺癌（ADC）进行组织学亚型分类的重要性。大约 70%的肺癌患者就诊时已处于晚期，通常只有小活检或细胞学标本作为唯一的诊断材料。目前尚不确定提出的 ADC 形态学亚型是否适用于小标本。本研究旨在评估 ADC 形态学亚型在细胞学标本中的适用性。
选择了 66 例手术切除和细胞学标本相匹配的新发原发性肺 ADC 患者的连续病例进行研究。根据 IASLC/ATS/ERS 分类确定主要形态模式。还评估了细胞学标本中恶性细胞的数量和百分比。
在 26 例（40%）中观察到在切除和细胞学标本中主要模式的 ADC 亚型一致，在 32 例（48%）中不一致。当标本中细胞数>200 个，并且与原发性或次要组织学模式相关时，一致性增加。在一致的病例中，腺泡模式最为常见，而不一致的病例主要为实性模式。
将 IASLC/ATS/ERS ADC 分类应用于细胞学标本具有挑战性，并且取决于细胞学标本的足够细胞数。识别实性和微乳头状模式在预后方面很重要，但在细胞学标本上可能不可靠且难以识别。未来需要进一步的研究，以建立用于在小标本上精确进行肺 ADC 亚型分类的可重复细胞学标准。
