Churg Andrew, Wright Joanne L, Ryerson Christopher J
*Departments of Pathology, Vancouver General Hospital and University of British Columbia †Departments of Pathology, St Paul's Hospital and University of British Columbia ‡Department of Medicine and Center for Heart Lung Innovation, University of British Columbia, Vancouver, BC, Canada.
Am J Surg Pathol. 2017 Oct;41(10):1403-1409. doi: 10.1097/PAS.0000000000000885.
Chronic (fibrotic) hypersensitivity pneumonitis (HP) and fibrosing interstitial pneumonias associated with connective tissue disease (CTD-ILD) can be difficult to distinguish in biopsy specimens. To investigate features that might separate these entities, 2 pathologists blinded to the diagnoses reviewed 16 cases of chronic HP and 12 cases of CTD-ILD. Fifteen predefined parameters were examined by morphometric point counting, analysis/cm of lung tissue, or presence/absence. Germinal centers were present in a minority of patients, but favored a diagnosis of CTD-ILD (7/12 CTD vs. 2/16 HP; odds ratio, 9.80 [95% confidence interval, 1.50-63.4]; P=0.02). The number of lymphoid aggregates/cm (4.4±3.1 vs. 1.4±1.0; P=0.001), volume proportion of plasma cells (0.076±0.058 vs. 0.031±0.023; P=0.031), and plasma cell: lymphocyte ratio (1.03±0.71 vs. 0.35±0.22; P=0.001) were all significantly higher in CTD compared with HP. A diagnosis of HP was more common in the presence of peribronchiolar metaplasia (12/16 HP vs. 4/12 CTD; odds ratio, 6.00 [95% confidence interval, 1.15-31.2]; P=0.033) and in patients with a greater fraction of bronchioles showing peribronchiolar metaplasia (0.41±0.33 vs. 0.16±0.27; P<0.001). Number of fibroblast foci/cm, distribution of fibroblast foci, pattern of fibrosis, presence of giant cells/granulomas, and volume proportion of lymphocytes or eosinophils did not distinguish chronic HP from CTD-ILD. We conclude that no single morphologic measure definitively separates chronic HP from CTD-ILD lung biopsies, but numerous foci of peribronchiolar metaplasia favor HP, while the presence of germinal centers, large numbers of lymphoid aggregates, or a high plasma cell: lymphocyte ratio suggests CTD-ILD. Multidisciplinary discussion is often necessary for accurate classification inthis setting.
在活检标本中，慢性（纤维化）超敏性肺炎（HP）和与结缔组织病相关的纤维化间质性肺炎（CTD-ILD）可能难以区分。为了研究可能区分这些实体的特征，2名对诊断不知情的病理学家对16例慢性HP和12例CTD-ILD病例进行了回顾。通过形态计量点计数、每厘米肺组织分析或存在与否检查了15个预定义参数。少数患者存在生发中心，但更倾向于CTD-ILD诊断（12例CTD中有7例，16例HP中有2例；优势比，9.80[95%置信区间，1.50-63.4]；P=0.02）。每厘米淋巴样聚集物数量（4.4±3.1对1.4±1.0；P=0.001）、浆细胞体积比例（0.076±0.058对0.031±0.023；P=0.031）以及浆细胞与淋巴细胞比例（1.03±0.71对0.35±0.22；P=0.001）在CTD中均显著高于HP。在存在细支气管周围化生的情况下，HP诊断更为常见（16例HP中有12例，12例CTD中有4例；优势比，6.00[95%置信区间，1.15-31.2]；P=0.033），并且在细支气管周围化生的细支气管比例更高的患者中也是如此（0.41±0.33对0.16±0.27；P<0.001）。每厘米成纤维细胞灶数量、成纤维细胞灶分布、纤维化模式、巨细胞/肉芽肿的存在以及淋巴细胞或嗜酸性粒细胞的体积比例并不能区分慢性HP和CTD-ILD。我们得出结论，没有单一的形态学测量方法能明确区分慢性HP和CTD-ILD肺活检，但大量细支气管周围化生灶支持HP诊断，而生发中心的存在、大量淋巴样聚集物或高浆细胞与淋巴细胞比例提示CTD-ILD。在这种情况下，多学科讨论对于准确分类通常是必要的。
