Multicentric Castleman disease (MCD) is a rare clinical entity characterized by a polyclonal lymphoid proliferation, leading to generalized lymphadenopathy, organomegaly and systemic symptoms. It has been reported in association with either other monoclonal or polyclonal lymphoid disorders, such as POEMS syndrome and immunoglobulin (Ig)G4-related disease. We present a patient showing a variant of MCD, sharing common features with POEMS syndrome and associated with the proliferation of IgG4-producing plasma cells.