Pediatric pathology: Specialized knowledge for the youngest

Interview with Professor Anette M. Müller, Director of the Center for Pediatric Pathology and Pathology at the University Hospital Bonn, Germany

When children are sick, their parents take them to a pediatrician. A pediatric pathologist is needed when pathology exams need to be conducted. This branch of pathology requires specialized knowledge. The Society for Pediatric and Fetal Pathologists is championing the transfer and preservation of this knowledge.


Photo: Anette M. Müller;  © private

Prof. Anette M. Müller; © private

Professor Anette M. Müller, President of the Society for Pediatric and Fetal Pathologists, talks about the characteristics of this profession and the current research in pediatric pathology at

Professor Müller, how does pediatric and fetal pathology differ from adult pathology?

Anette M. Müller
: Pediatric pathology is dealing with specimens of a different age group. It is defined as the diagnostic investigation of tissue development in a fetus, the placenta, the newborn as well as the child and adolescent. This is not simply an assessment of smaller tissue samples based on adult pathology standards. In his or her assessment of possible pathological changes, the pediatric pathologist needs to consider the morphology instead, which changes with physiological development and tissue differentiation. Especially with miscarriages, a correct diagnosis is very important in the counseling of parents for future pregnancies or the treatment of causes.

The same is true for the diagnosis of the placenta, that being the afterbirth. This assessment doesn’t just provide important clues on possible diseases of the newborn, the neonatologist can subsequently pursue. You can also deduct important information for future pregnancies from this. Yet other criteria oftentimes also apply when it comes to assessing samples taken from the stomach or colon of a child versus an adult.

What special pediatric pathology methods do you use to diagnose certain diseases?

: The methods used in pediatric pathology are the same that are being used in adult pathology. That said there are a number of special exams that are more frequently requested in pediatric pathology. There are diseases from congenital and pathological cilia for instance that may cause recurrent respiratory diseases. Cilia are tiny extensions on the cells of the respiratory tract. For their exam, pediatric pathologists use an electron microscope that is able to illustrate changes inside the cells and on the cell surface.
Photo: Child in hospital; Copyright: ltd

Pathologic investigations can be crucial for the children's treatment; © ltd

Another typical disease of the (small) child is a gastrointestinal disorder called Hirschsprung’s disease. During the development in the womb, nerve cells in the colon are missing. To diagnose this disorder, you need specific staining techniques for the tissue sample, so-called enzyme histochemistry. This staining method is very costly so that these exams are usually only performed in pediatric pathology, but not in adult pathology.

What effect do pathologic findings in children have in terms of their recovery?

: Just like with adults, today the (pediatric) pathologist determines the treatment for children. Let’s get back to the example of Hirschsprung’s disease. The correct diagnosis of agangliosis, the absence of ganglia, leads to the resection of the part of the bowel that doesn’t have nerves and subsequently is not able to move the bowel contents along. The child is healed after the intervention. Or let’s take the placenta again as an example: when you diagnose vascular obliteration in the child due to thrombosis in the placenta, the neonatologist can look specifically for the increasingly occurring neonatal cerebral infarctions common with this diagnosis.

During the conference of the Society for Pediatric and Fetal Pathologists in Berlin you talked about the impact of insulin therapy on a child’s development in pregnant diabetes patients at the annual convention of the German Society of Pathology. What conclusions did you reach in your research?

: We asked ourselves how certain proteins of endothelial cells in placental blood vessels are being expressed. This pertained to two proteins whose existence influences the seal of the vessels. Prior to that, we knew that both of these proteins are decreasingly expressed in female patients with diabetes. We discovered however that this is only the case with insulin therapy. On the one hand, this decreased expression promotes the vascularization of the placenta, which can definitely be a positive aspect, while it also promotes vascular permeability on the other. We are currently investigating whether this decreased expression presents more of a positive or negative aspect in the overall picture.

Are there specific diseases where it is beneficial to discover them very early on, preferably even before birth?

: One example for this is metabolic disorders. The sooner they are being detected, the sooner they can be treated. We recently had a case where we diagnosed a congenital metabolic disorder of the placenta. This diagnosis helped the pediatrician to immediately treat the child correctly. Another example is congenital tumors that might already develop in the womb. In this case, the attending gynecologist often diagnoses a tumor in a pre-birth ultrasound exam. The sooner this tumor can be operated on, the better. The tumor diagnosis by the pediatric pathologist subsequently makes it possible to immediately determine the best treatment.

How do you rate the potential of pediatric pathology for clinical diagnostics and treatment of children in your opinion?

: Pediatric pathology has great potential, but we need to make sure the specialized knowledge of pediatric pathologists is also being conveyed during studies. There are currently only a handful of specialized pediatric pathologists in the world with less than one-hundred of them residing in Germany. Not many of them are exclusively or predominantly focusing on samples of children. The risk is that this specific knowledge of pediatric pathology matters will be lost over time. That is why the Society for Pediatric and Fetal Pathologists is actively working on maintaining this knowledge in the German-speaking sector and passing it on to young pathologists.
Foto: Michalina Chrzanowska; Copyright: B. Frommann

© B. Frommann

The interview was conducted by Michalina Chrzanowska and translated by Elena O'Meara.