The histological features of splenosis.

This study presents a detailed histological analysis of two cases of splenosis, including one of the largest nodules to be reported. Splenosis may exhibit red and white pulp that appears histologically and immunohistochemically normal by routine methods, and a well-developed capsule and trabeculae may form. The capsule may be thicker than in the normal spleen but is otherwise indistinguishable and may contain fibrous, elastic and smooth muscle elements. These findings are in contrast to previously published works which have described poorly-developed white pulp, capsule and trabeculae in splenosis. The histological pattern may depend on the blood supply to the autotransplanted splenic tissue in the early days after implantation. The close resemblance that splenosis may show to an accessory spleen suggests that histological examination may have a limited role in the distinction between these two conditions.