A rare case of lethal idiopathic plasmacytic lymphadenopathy ( IPL) with polyclonal hyperimmunoglobulinemia with chronic renal failure is described. A 40-year-old woman who had suffered from upper airways disease was admitted to the Emergency Room with acute renal failure and hypergammaglobulinemia. She developed pericardial effusion, a pruritic rash, splenomegaly and fell into a coma after 6 days. Multiple myeloma, infection, collagenopathy, and coagulopathy were ruled out. Finally, a form of malignant hypergammapathy was suspected. At autopsy, lymph nodes were infiltrated by polyclonal plasma cells and lymphocytes, with erythrophagocytosis features; immunohistochemistry confirmed the plasma cells (CD138+), with a prevalence of kappa-positive cells, B (CD20+) and T (CD3+) cells. Kidneys showed advanced glomerulosclerosis containing similar infiltrates. The cause of death was IPL with polyclonal hypergammaglobulinemia and advanced renal failure. Similar cases are unusual, and possible medical liability associated with failure to diagnose and treat idiopathic plasmacytic lymphadenopathy deserves discussion and further studies. [ABSTRACT FROM AUTHOR]