Ceroid Histiocytosis of Spleen and Bone Marrow in Idiopathic Thrombocytopenic Purpura (ITP): A Contribution to the Understanding of the Sea-blue Histiocyte

Ceroid-containing histiocytes are described for the first time in the spleen and marrow of a patient with ITP. Ceroid results from the oxidation and polymerization of unsaturated lipids and may appear in histiocytes in a variety of diseases. With the Wright or Giemsa methods, ceroid granules are stained sea-blue, and ceroid-containing macrophages appear as “sea-blue histiocytes.” This sea-blue color is not pathognomonic for ceroid. Therefore, the finding of sea blue histiocytes in the bone marrow should be followed by histochemical studies to confirm the presence of ceroid. The spleen from a case of the recently described “syndrome of the sea-blue histiocyte” showed numerous ceroid-containing macrophages. In view of the lack of specificity of the sea-blue histiocyte, it is suggested that the syndrome be renamed “idiopathic ceroid histiocytosis of spleen and marrow.”