Clinical implication of idiopathic plasmacytic lymphadenopathy with polyclonal hypergammaglobulinemia: a report of 16 cases.

Idiopathic plasmacytic lymphadenopathy (IPL) with polyclonal hyperimmunoglobulinemia is considered identical to multicentric Castleman's disease (MCD) reported in western countries. Clinically, both IPL and MCD are characterized by multicentric lymphadenopathy, prominent polyclonal hypergammaglobulinemia, elevated erythrocyte sedimentation rate, elevated serum interleukin-6 concentration, bone marrow plasmacytosis, and various abnormal laboratory data such as anemia and positive autoantibodies. However, IPL has a significantly better 5-year survival rate than that of MCD. Moreover, none of the present 16 cases developed Kaposi's sarcoma or B-cell lymphoma. Histologically, the interfollicular area contains a sheet of polytypic mature plasma cells in both IPL and MCD. In MCD, the majority of lymphoid follicles had hyaline-vascular germinal centers. However, lymphoid follicles of IPL usually exhibit a hyperplastic germinal center. Immunostaining also demonstrated a normal/reactive follicular dendritic cell network pattern in the germinal center of IPL. Moreover, there were no human herpes virus-8-positive cells detected by immunohistochemistry. The overall clinicopathologic and immunohistochemical findings of our 16 cases suggest that IPL is distinct from MCD reported in Western countries.