In Memoriam: Valeer Desmet (1931-2024)

Professor emeritus Valeer Desmet peacefully passed away, aged 92, on March 9, 2024 in Leuven, Belgium. He was Professor of Histology and Pathology at the KU Leuven, Belgium. Valeer was born on September 11 in 1931 in Passendale, a rural village in the West of Flandres where World War I stood still for 2 years. Being an excellent student in Medicine, he was directed to work during his studies in the at-that-time only existing research lab of the Dutch-speaking University of Leuven Medical Faculty on Haematology and Blood Coagulation; the lab was headed by the late Prof Marc Verstraete. This research experience and the stimulating advice of the at-that-time dean, Prof Josue Vandenbroucke, also originating from Passendale, led him to start a research career. He chose to enroll in Histopathology, allowing him to examine diseases at the cellular level. He graduated as Doctor in Medicine at KU Leuven in 1957. He specialized in Anatomical Pathology under supervision of Prof Dr Meersseman at the UC Louvain, Prof Dr Delarue and Prof Dr Orcel at the Université de Paris, Prof Dr Harrison at the Postgraduate Medical School in London (where Sheila Sherlock was beginning as a hepatologist) and Prof Dr Brusselmans at KU Leuven. In 1963, he received his PhD diploma with a thesis entitled: 'Histochemical Study of experimental liver carcinogenesis'. In this groundbreaking study, he showed by utilising the butter yellow rat model that the proliferation of the smallest branches of the biliary tree, known as oval cells or hepatic progenitor cells, can lead to the formation of mixed tumours. This was the start of a long research career during which he investigated a diverse spectrum of liver diseases, including but not limited to liver cancer, hepatitis, biliary diseases and ductal plate malformations. In October 1963, Valeer Desmet assumed the role of head of the clinical Department of Pathology, alongside Prof Dr Jozef Lauweryns, and he founded the experimental laboratory for Histochemistry and Cytochemistry. While he harboured a special interest in liver pathology, Valeer also nurtured the talents of young colleagues, encouraging them to pursue their own clinical and research specialties. This mindset made the pathology department at Leuven internationally renowned, not only for liver pathology, but also across diverse fields including dermatopathology, GI pathology, haematopathology, soft tissue pathology, …each section being headed by one of his initial co-workers. By doing so, he attracted numerous fellows from all over the world, and especially from Italy. His personal journey through the liver is best described in the invited review "Master's perspective. The Amazing Universe of Hepatic Microstructure" published in Hepatology 2009.1Desmet V.J. The amazing universe of hepatic microstructure.Hepatology. 2009 Aug; 50 (PMID: 1964216): 333-344https://doi.org/10.1002/hep.23152Google Scholar One of Valeer's most notable accomplishments was through his close collaboration with his clinical colleagues, establishing joint 'clinicopathological meetings'. In those days, multidisciplinary team meetings were uncommon and not part of routine clinical practice. He excelled in linking the microscopic images to the clinical problems exposed to him. This innovative approach resulted, amongst others, in the first classification of hepatitis (chronic persistent vs. chronic aggressive hepatitis), even before the different hepatitis viruses were described. His seminal paper in 'The Lancet' co-authored with Prof Dr Jan De Groote, became one the most cited in the field.2De Groote J. Desmet V. Gedigk P. et al.A classification of chronic hepatitis.Lancet. 1968; 2: 626-628Google Scholar Valeer Desmet was one of the founders of the 'Gnomes', the International Liver Study group. This is a group of liver pathologists and hepatologists who circulate slides on a given topic to discuss the cases together at their annual meetings. He was also a member of numerous national and international scientific societies and served as president of the International Association for the Study of the Liver from 1984 to 1986. He was a member of the editorial board of several international scientific journals such as 'Journal of Pathology' and 'Hepatology', and was Chief of the editorial board of the journal 'Liver International'. Prof Desmet was frequently invited to give lectures at prestigious international liver meetings including EASL, AASLD, IASL and UEGW congresses. He received several awards, including Dr Honoris Causa of Universities of Kinshasa and Cagliari, and being named Honorary Fellow of the Royal College of Pathologists UK. In 2004, he was the Honorary President at the EASL meeting in Berlin. Since 1963, initially as assistant Professor and later as full Professor from 1967, Valeer Desmet shared his knowledge of Histology and Pathology by teaching countless students at the Medical Faculty and Dentistry School. His very clear and nicely illustrated courses inspired thousands of students over the years, leaving a legacy in the field of medical education. When he retired in 1996, I (Tania Roskams) had the honour to take over the clinical liver pathology and the liver research unit. Since the start of my training as pathologist in 1989, I cannot count the hours we spent at the microscope together, analysing difficult cases, or discussing research results. After a full career as a liver pathologist and researcher, he was the best teacher I could imagine. Always open to 'crazy ideas', guiding but not steering, giving opportunities to his young co-workers. He was always very open-minded and committed to sharing his knowledge and insights with fellow researchers, pathologists and clinicians. This is witnessed by all the positive and friendly comments we received. Following his retirement, he still liked helping with difficult liver biopsies, all while cherishing moments with his family. He liked cooking for them with fresh vegetables from his garden. With the passing of Prof Em Dr Valeer Desmet, we lost one of the most brilliant but, at the same time, most humble members of our community. He will be missed by many of us. Our condolences go out to his beloved wife Rose, his 5 children and 18 grandchildren. We thank Prof Olivier Govaere for carefully reading the text.