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Paul C. Stromberg, DVM, PhD, DACVP
Department of Veterinary Biosciences
The Ohio State University College of Veterinary Medicine
Columbus, OH.

Daniel R. Rissi, DVM. MS, PhD, DACVP
Department of Pathology
University of Georgia College of Veterinary Medicine
Athens, GA.

Claudio S.L. Barros, DVM, PhD, DACVP
Laboratory of Anatomic Pathology
School of Veterinary Medicine and Animal Science
Federal University of Mato Grosso do Sul
Campo Grande, MS, Brazil.

Bruce H. Williams, DVM, DACVP
Joint Pathology Center
Washington, D.C.

Cover image: Pandora by Lawrence Alma-Tadema, 1881 (public domain).

            It really all started with Paul Stromberg. Sure, people had been describing slides and passing the Americal College of Veterinary Pathologists (ACVP) certifying examination (the only one in existence in the world at the time) since 1949 – and textbooks used wonderful, if unapproachable, levels of prose possessed by only a few pathologists, while most toiled in the autopsy room, where diagnosis was king and “fancy descriptions” were a burden and a speed bump.

            I met Paul in 1989 as a first-year AFIP resident when he was doing a sabbatical at the US Army Research Institute of Infectious Disease at Ft. Detrick. For reasons unknown (and annoying) to me at the time, I was pulled away from my cases to hop in a car and go see “this guy from Ohio State who is some professor or something.” Little did I know that lecture was to change my life, and improve me as a pathologist, in so many ways.

            I like to say that I knew Paul when he had grey hair, but that is not my true recollection of our first meeting. My memory was that of a white haired civilian busy pulling kodachromes from sleeves in a binder and stuffing them into carousels. Then he started lecturing, and it literally changed my life. Gross description was laid out for me like no one else had ever done – simple, systematic, and easy to understand. Tissue colors mean one thing. If a lesions bulges, something’s been added – cells, fluid, rarely air; if it is depressed, you have lost tissue. Some lesions are well-demarcated because of the great differences between the lesion and the tissue around it (like a metastatic tumor focus), or poorly demarcated (because the tissue is similar to its surroundings). Let’s not forget Paul’s Fine Arts 101 tip – dark colors always overshadow light ones, so when you see hemorrhage, you are almost always seeing necrosis as well (the light areas of necrotic debris just can’t compete against the dark red of hemorrhage). And his pictures – they were like nothing else. At the AFIP, I was used to looking at kodachromes, twenty or thirty years prior, with tissues photographed on old towels or in the grass, and by pathologists who shot everything in situ and from a lofty height (approaching satellite photography). Those old slides all had a deep red tinge due to having been reproduced so many times. But Paul’s images were art – a single organ placed against a black background (which still makes most lesions pop), a lesion you couldn’t miss, and everything in crisp color. I still use many of Paul’s kodachromes today (now digitized) in my lectures.

            No one in the room that day, trainees or fully qualified pathologists, had seen a lecture like that before – not only did Paul have the diagnosis (which we all still struggled with), but he would painstakingly explain how those lesions came to be – the type of necrosis or cellular proliferation, the cellular and non-cellular components that came together to form a particular lesions – something he would later call the “macroscopic-microscopic” correlation.

            I have always likened a first-year-resident’s head to a snow globe – facts swirling around in constant motion, without apparent contact or cohesion with each other – that day, the snow globe quieted for me, and I saw the structures within – the basics of descriptive pathology – for the first time.

            In thirty years in veterinary pathology, I have had a marvelously charmed career. In the second year of my residency, my department head, John Pletcher, decided that there should be an actual course for teaching description to residents like me, and anyone else who wanted to take the ACVP certifying exam, where this new language comprised 25% of the test. The first year was just military instructors, and a bit rough. Realizing some outside expertise was needed, Dr. Pletcher added Paul Stromberg in 1992, just before I took my exam in September, and once again I got to watch that brilliant lecture. It was four hours of clarity for a panicked resident, and the sixty or so residents sitting around me (1992 was also the first time we had civilian students from other universities beginning to populate the course).

            John retired from active duty in 1993, and asked me if I would take over the course at the AFIP. That was heady stuff for a newly minted major and a newly certified ACVP diplomate, but I realized it would be a chance to work alongside Paul, a pairing has lasted for over 25 years. The Descriptive Course came every June, with Paul doing the lectures on gross description, and myself covering microscopic descriptions, including ultrastructure. In addition to teaching this very specialized material, Paul, being an excellent diagnostic pathologist, would also teach at the Gross Pathology Review Course in March of each year. He could lecture on anything; one year it was dogs and cats, the next year horses, the next year ruminants, and occasionally lab animal topics – and always with those beautiful images. Unlike other speakers, Paul never used any word slides – just full screen image after full screen image – he was a marvel to behold.

            Working closely with Paul, watching him lecture and grading tests with him often late into the night, a lot of his knowledge rubbed off (or I just outright stole it), but it made me a much better pathologist in my own right. Every Gross Path Review Course started with my lecture on Macroscopic Descriptive Techniques – an almost rote, but condensed version of Paul’s original thoughts – color, elevation, and special features etc. , but with my own illustrations. At the end of the course there was a 100-slide exam, where I could hammer these concepts into the assembled participants. Much of what I taught was Paul’s – and I fully admit that my work in this area 25 years later is still derivative of Paul’s. He thought it all up – I just added another voice to the chorus, and taught many others over the years to sing as well.

            Those years of Descriptive Path were fun – we started a biannual European course in 1994 – I think I taught the first one alone and Paul’s material was well received. He joined the next one in 1996, and only missed one after that. In 1994 we also expanded Paul’s role to a full day when he rolled out another killer lecture on “Macroscopic-Microscopic Correlations” pairing up gross, subgross, and microscopic images of the same lesion to explain why various gross lesions look the way they do.

            As the ACVP test changed, so did the course. When cytology was added to the list of potential questions in the exam, we recruited Don Meuten to cover cytology – another great pathologist. Shortly afterward we had to add a lecture on immunohistochemistry, and even more great speakers from the AFIP – Dana Scott, Jo Lynne Raymond, and Sarah Hale in various years, all providing stellar support on a course that in most years exceeded its cutoff of a hundred participants.

            I can’t tell you how many students Paul taught descriptive pathology to around the world – one year Paul and I went to Brazil to teach the course and graded papers in Portuguese (which neither of us spoke). India was a fun trip to, teaching on monocular scopes with mirror illumination was a thrill for both of us.

            It was a great run on the Descriptive Course for 25 years. While other, younger pathologists have now assumed the mantle of the annual Descriptive Course due to the recent changes in the ACVP certifying exam, Paul is still in great demand around the world for his material, and I still teach it religiously to my residents and anyone else who will listen.

            This tale, in its own verbose and reverential way, brings me to this book and my other co-authors, Dan Rissi and Claudio Barros. This edition, I suspect, is almost all Dan Rissi – a great young pathologist who is as dedicated to teaching as any pathologist I have ever known. He has taken the concepts of gross description that Paul codified so many years ago and fleshed them out with outstanding examples that rival Paul’s original images. His mentor and one last co-author, Claudio Barros, is simply a pathology god. The country of Brazil is home to so many outstanding pathologists, easily rivaling any other country in the world. The one thread among all these fine Brazilian pathologists is their love and admiration of Claudio – who truly embodies the skill, logical thinking, and just overall “cool” of our colleagues in Brazil. Whenever our paths cross, I simply stand in awe of the man.

            The first edition of “Opening Pandora’s Box” is a fine work which does great honor to Dan, its primary author, as well as the rest of us who have spent their career teaching these tenets to legions of students. Being a co-author with these three outstanding pathologists is truly an honor for me, and I am confident that even more generations of veterinary pathologists will benefit from the concepts and teachings contained herein.

Bruce Williams, 2019


Pathology is the branch of medicine that studies the causes, mechanisms, and effects of diseases in an organism. It is a broad definition but reflects the character of this medical specialty that has its roots firmly attached to basic sciences such as molecular and cell biology, biochemistry, physiology, and anatomy.

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Gross Description of Tissue Changes

Before you initiate your description, keep in mind that some tissue changes might require more descriptive details than others. It all depends on how complex the changes are. Think of a well-known piece of art or landmark such as Da Vinci’s Mona Lisa or the Statue of Liberty.  You do not need too much effort to describe these two objects since you assume that virtually everyone knows these famous works of art.

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Interpretation of Tissue Changes

The pathologist should be able to recognize not only lesions, but also changes referred to as non-lesions, lesions with little or no clinical and diagnostic significance, and postmortem artifacts. 

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Writing a Pathology Report

The pathology report will compile the description of all gross anatomic changes, as well as results from the histology examination and other ancillary tests that were used to reach a final diagnosis. All the information available will be used to comment on the main findings and their relevance to the case. Occasionally no diagnosis will be possible based on the available data and that is part of the job. 

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We hope that by opening that box everyone – veterinary students, veterinarians, pathology residents, and pathologists – may be able to transform the apparent unveiling chaos into a solvable puzzle by using this book as a basic source of guidance and information during their professional training or professional life.

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Next: Introduction