Franks Teri J, Galvin Jeffrey R
Department of Pulmonary & Mediastinal Pathology, Armed Forces Institute of Pathology, 6825 16th Street NW, Washington, DC 20306, USA.
Department of Radiologic Pathology, Armed Forces Institute of Pathology, 6825 16th Street NW, Washington, DC 20306, USA; Department of Diagnostic Radiology, and Department of Internal Medicine, Division of Pulmonary/Critical Care Medicine, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA.
Surg Pathol Clin. 2010 Mar;3(1):187-98. doi: 10.1016/j.path.2010.03.005. Epub 2010 Jul 7.
Hypersensitivity pneumonitis is a diffuse, granulomatous interstitial lung disease caused by repeated exposure to a wide spectrum of environmental antigens. Clinical, radiologic, and histologic findings are quite variable and mimic many other diseases; therefore, diagnosis depends on a constellation of findings rather than a single defining feature. High-resolution computed tomography (HRCT) plays a critical role in this setting. The presence of centrilobular nodules, multifocal ground glass opacities, and evidence of air trapping in the expiratory phase of respiration is highly suggestive of hypersensitivity pneumonitis and can direct clinicians to the correct diagnosis. For the pathologist, typical HRCT findings not only corroborate the diagnosis of hypersensitivity pneumonitis when the characteristic triad of airway-centered chronic interstitial inflammation, interstitial poorly formed non-necrotizing granulomas, and organizing pneumonia is present on biopsy, but also improve diagnostic confidence in biopsies lacking components of the diagnostic histologic triad. Importantly, the presence of focal or unilateral imaging findings should prompt a careful search by the pathologist for an infectious etiology, thus avoiding errors in determining the significance of granulomas on biopsy. This article reviews the essential radiologic and pathologic findings in hypersensitivity pneumonitis, discusses the primary considerations in the differential diagnosis, and offers an approach to biopsy evaluation.
过敏性肺炎是一种弥漫性、肉芽肿性间质性肺病，由反复接触多种环境抗原引起。临床、放射学和组织学表现差异很大，可模仿许多其他疾病；因此，诊断取决于一系列表现而非单一的决定性特征。在这种情况下，高分辨率计算机断层扫描（HRCT）起着关键作用。小叶中心结节、多灶性磨玻璃影以及呼气期气体潴留的证据高度提示过敏性肺炎，可指导临床医生做出正确诊断。对于病理学家来说，典型的HRCT表现不仅在活检出现以气道为中心的慢性间质性炎症、间质内形成不良的非坏死性肉芽肿和机化性肺炎这一特征三联征时支持过敏性肺炎的诊断，而且还能提高对缺乏诊断性组织学三联征成分的活检的诊断信心。重要的是，局灶性或单侧影像学表现的出现应促使病理学家仔细寻找感染病因，从而避免在确定活检中肉芽肿的意义时出现错误。本文综述了过敏性肺炎的基本放射学和病理学表现，讨论了鉴别诊断的主要考虑因素，并提供了活检评估方法。
