We describe one patient with localized Castleman's disease (CD) of the mixed hyaline vascular and plasma cell type located at the mesentery of the small bowel, associated with systemic amyloidosis and nephrotic syndrome. A true nephrotic syndrome has rarely been reported in patients with CD. In the literature, it has been suggested that clinical and laboratory manifestations generally improved after surgical resection of the tumor. However, in our case, clinical and laboratory findings did not regress after operation followed by colchicine therapy.