Sarcoidosis is a complex disease and much concerning this disease is still unknown. It can be difficult to diagnose patients. In some cases it is necessary to diagnose someone using biopsies, to determine the presence of granulomas under the microscope, with 100% certainty. However, sometimes this biopsy is considered to difficult or to dangerous. Think about obtaining brain- or nerve tissue in case of involvement of the nervous system (neurosarcoidosis) in some, but not all cases. Furthermore, not all patient respond wel to treatment. Especially in some rare manifestations of the disease this has not been investigated yet. To understand the disease better we are conducting scientific research of chronic inflammatory disorders, like sarcoidosis. We hope to collect more knowledge about this disease to ultimately improve patient care.