CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Dr. Truong
Other sections of the atlas, too, contain new information on antibody-mediated rejection. “This is a critical area in transplant pathology, and over the past few years there have been several seminal studies that have provided novel insights into this pathologic process,” says Dr. Truong, who contributed to the kidney section. These new findings are incorporated into the updated Banff Classification of Renal Allograft Pathology published in 2014, he says, “leading to revised and improved diagnostic criteria, together with their practical applications in renal transplant biopsy interpretation. These important developments are thoroughly reviewed in various chapters of this atlas.”
Dr. Cagle and his co-editors were nearing completion of the atlas’ manuscript when, in April 2014, the meeting report of the Banff Conference on Allograft Pathology was issued. “The Banff report is based on a consensus conference of transplant experts and updates criteria for rejection classification and other recent advances,” Dr. Cagle says. “Findings in this report were taken into account in revising our manuscript.”
One newly described entity that appears in the lung section of the atlas: restrictive allograft syndrome. “The main pathologic finding is fibroelastosis of the visceral pleura,” Dr. Cagle explains, “which hampers the ability of the lung to expand and exchange gas. We have some other findings that we can see as well, but that’s the one that sets this apart, and it’s something that might not be fully appreciated by pathologists if they’re not aware of this.”
Among the other sections of the atlas that contain newly described entities or other new findings are: in heart, cardiac allograft vasculopathy; in kidney, glomerulitis and transplant glomerulopathy; in liver, donor organ evaluation, preservation injury, and antibody-mediated rejection; and in lung, lung-transplant–associated infections and lung-transplant–associated organizing pneumonia.
From chapter on liver donor organ evaluation (to be published next month in cap today): Mild portal inflammation. Donor organs may exhibit mild portal inflammation with or without bile ductular proliferation. These changes are common and are not a contraindication to transplantation.
From chapter on lung-transplant–associated infections: Low-power image of lung wedge biopsy in a lung transplant patient with viral infection, showing interstitial pneumonia and necrosis with areas of hemorrhage.
To Dr. Yerian, the value of the atlas rests in large part on its illustrations. “We wanted to provide enough text to be informative, but not an extensively detailed, heavily referenced discussion on each topic, because that’s already available out there,” she says. “We just wanted enough text to support an interpretation of the pictures. The pictures are the magic of what we do.”
How so? Well, “one of the things I observe as a liver pathologist is that acute rejection doesn’t always look like the same thing; it’s not a picture-matching diagnosis, where if you see it once, you always recognize it,” she says. “There’s quite a spectrum of appearances. So what we try to do in the atlas is give a sense of the spectrum of morphology you can see with any given entity. In many cases, the reader will find more than one picture of a given entity, to really try to illustrate the spectrum of changes you can see. You can list the features, but that’s not going to get you far enough; you need to see the spectrum of changes, because there are subtleties in the morphology that we’re just not great at articulating with words yet. We aim to see as many examples, as much of the spectrum as possible, in order to better understand what an entity is and, even more importantly, what it isn’t.”
One such spectrum: the many patterns of immune-mediated graft injury that may be seen in transplanted livers, “including patterns that have more prominent centrilobular distribution,” she says. “Plus, there’s variation among patients. Some might have more prominent bile duct damage, whereas endotheliitis might be more prominent in others.”
Then, too, she continues, “In early acute rejection episodes, you commonly see a prominent mixed portal infiltrate with very large, active appearing lymphocytes. But as time progresses, we can see an evolution toward a more mononuclear infiltrate, more mature and lymphocyte-predominant, and more reminiscent of a chronic hepatitis pattern. That’s a really common and important diagnostic problem.”
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Anne Ford is a writer in Evanston, Ill. To order a print book (PUB124), go to www.cap.org (“Shop” tab) or call 800-323-4040 option 1. For members, $76; for nonmembers, $95. To order an ebook, go to ebooks.cap.org ($65).