Differential diagnosis of granulomatous diseases

Despite advances in the understanding of the pathophysiology, granulomatous diseases remain a diagnostic challenge for the clinician as well as for the pathologist. However, establishing the correct diagnosis of these diseases is a crucial prerequisite of targeted therapy. It is particularly essential to distinguish between an infectious and a non-infectious cause, since anti-infectious and anti-inflammatory or immunosuppressive approaches are opposing. Failure to establish the correct diagnosis can lead to adverse consequences for the patient. An interdisciplinary approach and a critical assessment of clinical, laboratory-chemical, microbiological, imaging, and anatomical-pathological findings are crucial for the evaluation of granulomatous disorders. This overview summarizes important landmarks and their value in the interplay of arriving at the correct diagnosis.