Departments of *Pathology ‡Surgery, Division of Transplantation, University of California at San Francisco, San Francisco, CA †Department of Public Health and Preventive Medicine, SUNY Upstate Medical University, Syracuse, NY.
Am J Surg Pathol. 2017 Mar;41(3):365-373. doi: 10.1097/PAS.0000000000000802.
Although donor livers with <30% large droplet macrovesicular steatosis (MaS) and/or small droplet MaS (irrespective of percentage) are considered safe to use, this consensus is based on variable definitions of MaS subtypes and/or without a reproducible scoring system. We analyzed 134 donor liver biopsies from allografts transplanted at University of California at San Francisco between 2000 and 2015 to determine whether large and/or small droplet MaS is a risk factor for poor outcomes. Large droplet MaS was defined as a fat droplet occupying greater than one half of an individual hepatocyte, with nuclear displacement, and scored as the percentage of total parenchymal area replaced by large fat droplets on ×40 magnification. Small droplet MaS was defined as 1 to several discrete fat droplets, each occupying less than one half of an individual hepatocyte, and scored as the percentage of remaining hepatocytes (ie, hepatocytes not occupied by large fat droplets) containing small fat droplets on ×200 magnification (ie, small droplet MaS is the percentage of "remaining hepatocytes" with small fat droplets, and "remaining hepatocytes" is defined as 100% minus percent large droplet MaS). Thus, total MaS equals the sum of large and small droplet MaS, which cannot exceed 100%. Electronic medical records were reviewed to determine outcomes. There was an increased risk for acute cellular rejection (hazard ratio=2.5, P=0.0108) and bile duct loss suggestive of chronic ductopenic rejection (hazard ratio=2.4, P=0.0130) in donor livers with ≥30% small droplet MaS. Large droplet MaS (up to 60%) was not associated with adverse outcomes. Patient survival was not adversely affected by steatosis. Excellent agreement on the estimation of large (weighted κ=0.682) and small droplet MaS (weighted κ=0.780) was achieved. Our approach to donor steatosis scoring can identify liver allograft recipients at increased risk for rejection and highlights the importance of distinguishing between small and large droplet MaS in this evaluation.
尽管 <30%大泡性肝细胞脂肪变（MaS）和/或小泡性 MaS（不论百分比如何）的供体肝脏被认为是安全的，但这种共识是基于 MaS 亚型的可变定义和/或缺乏可重复的评分系统。我们分析了 2000 年至 2015 年期间在加利福尼亚大学旧金山分校移植的同种异体移植物的 134 份供体肝活检，以确定大泡性和/或小泡性 MaS 是否是不良结局的危险因素。大泡性 MaS 的定义为占据单个肝细胞一半以上的脂肪滴，伴有核移位，并按×40 放大倍数大脂肪滴取代的总实质面积的百分比进行评分。小泡性 MaS 被定义为 1 至几个离散的脂肪滴，每个脂肪滴占据单个肝细胞的不到一半，并按×200 放大倍数的剩余含小脂肪滴的肝细胞（即，不被大脂肪滴占据的肝细胞）的百分比进行评分（即，小泡性 MaS 是含小脂肪滴的“剩余肝细胞”的百分比，而“剩余肝细胞”定义为 100%减去大泡性 MaS 的百分比）。因此，总 MaS 等于大泡性和小泡性 MaS 的总和，不能超过 100%。回顾电子病历以确定结局。在≥30%小泡性 MaS 的供体肝脏中，发生急性细胞排斥反应的风险增加（危险比=2.5，P=0.0108）和提示慢性胆管缺失性排斥反应的胆管丢失风险增加（危险比=2.4，P=0.0130）。高达 60%的大泡性 MaS 与不良结局无关。脂肪变性不会影响患者的生存。对大泡性 MaS（加权κ=0.682）和小泡性 MaS（加权κ=0.780）的评估具有极好的一致性。我们的供体脂肪变性评分方法可以识别出排斥反应风险增加的肝移植受者，并强调在这种评估中区分小泡性和大泡性 MaS 的重要性。
