Castleman disease (CD) is a rare group of lymphoproliferative disorders subdivided based on clinical features. Although not fully understood, the pathogenesis of both CD and Crohn's disease involves a combination of immune dysregulation and infectious and environmental factors. Interleukin-6, a proinflammatory cytokine, is associated with both diseases and can serve as a common therapeutic target in CD. We report a rare case of coexisting unicentric Castleman disease in a young patient with Crohn's disease.