Morphologic findings in a patient with primary, type 5 hyperlipoproteinemia of Fredrickson and Lees, reported for the first time, include marked splenomegaly with extensive ceroid histiocytosis, fatty metamorphosis and early fibrosis of the liver, and increased numbers of foam cells in the bone marrow. Diseases associated with accumulation of ceroid in various tissues are tabulated. We stress that, with the Wright or Giemsa methods, ceroid granules are stained sea-blue and ceroid-containing macrophages appear as “sea-blue histiocytes.” This staining reaction is not pathognomonic for ceroid. The spleen from a patient with “the syndrome of the sea-blue histiocyte” contained numerous ceroid-containing macrophages. In view of the lack of specificity of the “sea-blue histiocyte,” it is suggested that, pending its validation, “the syndrome of the sea-blue histiocyte” be renamed “idiopathic ceroid histiocytosis of spleen and marrow” or “Silverstein’s syndrome.”