Multicentric Castleman's disease (MCD) is a rare polyclonal lymphoproliferative disorder that is typically accompanied by an overproduction of circulating cytokines (mainly interleukin-6). We here report the case of a 40-year-old HIV-negative woman with pulmonary manifestation of MCD. There is no standard treatment for MCD. In our patient, various treatment courses with immunomodulatory drugs were unsuccessful. Finally, treatment with the interleukin-6 receptor antibody tocilizumab has resulted in continual clinical improvement over the last 5 years.