最大径≤1cm的纯磨玻璃密度肺腺癌病理分类及CT征象特点分析

Analysis of histopathologic subtypes and CT characteristics of lung adenocarcinomas presenting as pure ground-glass nodule of 1 cm or less in maximal diameter

目的探讨最大径≤1cm的纯磨玻璃密度肺腺癌的病理分类及CT征象特点。方法回顾性分析2011年3月到2015年2月95例经手术病理证实为肺腺癌，且最大径≤1cm的纯磨玻璃密度结节（pGGN）患者（共97个病灶）的CT、病理及临床资料，97个病灶中有不典型腺瘤样增生（AAH）19个、原位腺癌（AIS）31个、微浸润腺癌（MIA）19个和浸润性腺癌（IPA）28个，50个（51．5％）为浸润前病变（AAH＋AIS），47个（48．5％）为浸润性病变（MIA＋IPA）。病灶大小和密度的病理亚型间比较采用单因素方差分析；浸润前病变和浸润性病变大小的比较采用两个独立样本t检验；病灶位置、空泡征、空气支气管征、血管改变、病灶边缘及瘤肺界面的病理亚型间比较采用卡方检验；ROC曲线分析用于评估鉴别浸润前病变和浸润性病变的最佳界值。结果97个pGGN中，各病理亚型问病变密度、空泡征、空气支气管征及边缘差异均无统计学意义（P值均〉0．05）。AAH、AIS、MIA和IPA病变平均大小分别为（0．72±0．19）、（0．82±0．14）、（0．84±0．11）和（0．85±0．16）cm，差异具有统计学意义（F=3．16，P=0．028）。各亚型出现血管改变分别为2、11、10和17个病灶，差异有统计学意义（X2=13．22，P=0．004）。瘤肺界面清楚的病灶分别为10、24、17、26个，差异具有统计学意义（x2=12．67，P=0．005）。鉴别浸润前病变和浸润性病变大小的界值为0．82cm，敏感度为61．7％，特异度为62．0％。结论≤1cmpGGN肺腺癌中，病变大小、血管改变和瘤肺界面有助于鉴别浸润前病变和浸润性病变。

Objective To evaluate the correlations between CT features and histopathologic subtypes of lung adenocarcinomas presenting as pure ground-glass nodules （pGGN） of 1 cm or less in maximal diameter. Methods CT appearances, pathology and clinical data of 95 patients （97 lesions） who underwent curative resection of lung adenoearcinomas presenting as pGGN≤1cm in diameter from March 2011 to February 2015 were retrospectively analyzed. Of the 97 lung adenocarcinomas, there were 19 atypical adenomatous hyperplasia （AAH） （19.6%）, 31 adenocarcinoma in situ （AIS） （31.9%）, 19 minimally invasive adenocareinoma （MIA） （19.6%） and 28 invasive pulmonary adenocareinoma （IPA） （28.9%）. Fifty （51.5%） were preinvasive （AAH ＋ AIS） and 47 （48.5%） were invasive （MIA ＋ IPA）. Lesion size and density were compared among pathologic subtypes using analysis of variance （ANOVA）. Lesion size were compared between preinvasive and invasive lesions using 2-independent samples t-test. Lesion location, presence of bubble-like sign, air bronchogram, vessel changes, margin, and tumor-lung interface were compared among histopathologic subtypes using chi-square test. Receiver operating characteristic （ROC） curve analysis was performed to evaluate the cut-off point of size in discriminating preinvasive lesions from invasive lesions. Results Of the 97 lesions, there were no statistically significant differences among histopathologic subtypes in terms of lesion density, presence of bubble-like sign, air-bronchogram, and margin （P〉0.05）. Mean size of AAH, AIS, MIA and IPA was （0.72±0.19）, （0.82±0.14）, （0.84±0.11） and （0.85±0.16） cm respectively. There were statistically significant differences among histopathologie subtypes in terms of lesion size （F=3.16, P=0.028）. The vessel changes occurred in 2 of AAH, 11 of AIS, 10 of MIA and 17 of IPA. There were statistically significant differences among histopathologic subtypes in terms of vessel changes （X2=13.22, P=0.004）. Lesions with clear tumor-lung interface were in 10 of AAH, 24 of AIS, 17 of MIA, and 26 of IPA. There were statistically significant differences among histopathologic subtypes in terms of tumor-lung interface （X2=12.67, P=0.005）. The optimal cutoff value of lesion size for differentiating preinvasive lesions from invasive lesions was 0.82 cm （sensitivity, 61.7%; specificity, 62.0%）. Conclusion Lesion size, vessel changes, and lung-tumor interface may indicate the invasiveness of lung adenocarcinoma presenting as pGGNs of ≤ 1 cm in diameter.