Multicentric Castleman disease (MCD) is a lymphoproliferative disorder of incompletely understood etiology and with various clinical presentations. The best therapeutic option for this disease is not well established. MCD is known to be associated with autoimmune phenomena. A 70-year-old female patient of MCD with progressive nodal disease associated with autoimmune thrombocytopenia failed steroid treatment and showed a transient response to intravenous immunoglobulin. The patient achieved complete recovery of her platelet count and a very good response in nodal disease after 3 weekly doses of anti-CD-20 antibody (rituximab). Anti-CD20 antibody treatment could be a good therapeutic option for MCD, mainly when associated with immune-related disorders.