Multiple Complications of Crohn's Disease and the Need for Early and Continuous Multidisciplinary Undertaking.

Crohn's disease is an inflammatory disease that typically affects the bowels but can also have many different extraintestinal manifestations. One of those complications is immunoglobulin A nephropathy (IgAN), which is one of the most encountered renal lesions in the setting of Crohn's disease. Another point of focus for Crohn's patients is the risk of cancer, with a higher risk of colorectal cancer but also extraintestinal neoplasia such as hepatobiliary, hematological, and urinary tract neoplasia. We present the case of a young patient suffering from long-term Crohn's disease and subsequent IgAN leading to end-stage kidney disease and hemodialysis. The patient was diagnosed young and had undergone multiple surgeries and different treatments in various countries. He then presented in our center already with advanced chronic renal failure from IgAN that was unknown due to poor multidisciplinary follow-up. Shortly after starting hemodialysis, he developed a large abdominal mass, first thought to result from Crohn's-related fistula. This mass turned out to be a urachal adenocarcinoma, a rare type of bladder cancer with an especially poor prognosis. It is not known whether this type of cancer is associated with either Crohn's disease or IgAN, and no such association has been previously described. The treatment of urachal cancer usually relies on surgery, with the addition of chemotherapy in some cases. Unfortunately for our patient, his case was already so advanced at the moment of diagnosis that he was excluded from curative treatment and quickly passed away thereafter. This case illustrates many important aspects of the rigorous follow-up that is needed for Crohn's patients, with regular check-ups, screening investigations, and the need for multidisciplinary evaluation. Furthermore, it describes the development of a rare type of cancer in the setting of Crohn's disease and IgAN, with no prior established link between these different pathologies.