When the German surgeon Max Wilms described a particular kidney cancer in children in his 1899 work “Die Mischgeschwülste,” he did not yet know that it would later be named after him. He probably had even less idea that the tumor, which was inevitably fatal at the time, could usually be beaten under today’s therapy. A cancer diagnosis is always terrible at first, even more so when it comes out of the blue and affects a child. But in the case of Wilms’ tumor (or nephroblastoma), those affected can at least have hope from the start: It is now one of the cancers with the best chances of cure.
How does this disease develop and who is affected?
It has been known for some time that nephroblastoma arises from various basic tissues of the embryo (hence the term “mixed tumor”), which normally either regresses or develops into definitive tissue by the time of birth. Depending on the stage of development of the tumor cells and the tissue of origin, the tumor can look very different and multiform under the microscope.
Exactly how it happens that the germinal tissue in parts of the kidney does not develop normally has not yet been clarified. However, it is now known that genes with the ominous names WT1 and WT2 on chromosome number 11, and presumably others, play a role. What also speaks for a congenital component is that not so rarely other malformations are present at the same time, e.g. the absence of an eye lens, a giant growth of only one side of the body or a horseshoe kidney.
Even though Wilms’ tumor is the most common kidney cancer in children, it occurs rather rarely, with 1 case per 100,000 children. In Germany, this corresponds to an annual incidence rate of 110 children. A good third of those affected are between 1 and 5 years old, 16% are infants. In 5% of cases, both kidneys are affected.
How does the disease manifest?
Treacherously, the tumor usually causes no symptoms for a long time – in about 10%, the diagnosis is an incidental finding on palpation during a routine examination. By far the most common symptom is an increase in abdominal girth, which is often initially misinterpreted as a bloated abdomen or even attributed to good nutritional status. Less common are digestive complaints, blood in the urine, or abdominal pain.
