Lymph node siderosis in trypan blue treated rats.

The accumulation of iron in the lymph nodes of trypan blue treated rats was examined as a possible experimental counterpart of the lymph node siderosis which occurs in patients with Hodgkin's disease. Lymph nodes removed from the hilus of the liver, retrosternal area, axilla and root of the small bowel mesentery were examined histologically for iron in rats receiving 6-20 subcutaneous injections of trypan blue at biweekly intervals and in control rats. An increase in erythrophagocytosis accompanied by a progressive increase in the amount of stainable iron was found in the RE cells of nodes located in the lymphatic outflow tract of the liver. As in patients with Hodgkin's disease, an increase in erythrophagocytosis together with the prolonged retention of iron by RE cells appears to account for the accumulation of iron in the lymph nodes of trypan blue treated rats.