[Polyclonal plasmacytosis in peripheral blood and leukocytoclastic vasculitis in Castleman's disease].

A 62 year-old man had fever, splenomegaly, systemic lymphadenopathy and palpable petechiae. Laboratory studies showed leukocytosis (10,200/microliters) with plasma cells (23%) and polyclonal gammopathy. Southern blot analysis of peripheral blood mononuclear cells showed no rearrangement of immunoglobulin genes, indicating polyclonal plasmacytosis in peripheral blood. A diagnosis of Castleman's disease was made by the cervical lymph node biopsy, which showed onion-skin structures in the germinal centers and plasmacytosis in the interfollicular region. A skin biopsy of the purpura lesion disclosed leukocytoclastic vasculitis. This is an unusual case of Castleman's disease presenting plasmacytosis in peripheral blood and leukocytoclastic vasculitis.