Solution: Splenosis is autotransplantation of splenic tissue to other sites in the body, often within the abdomen, but can occur in the thorax, and body wall as well. In this case there is evidence of previous splenic trauma with a small, lobulated residual spleen in the left upper quadrant and an avidly enhancing mass in the right perirectal space. Based upon these imaging findings, one would be suspicious for splenosis rather than metastatic disease, but this can be confirmed with a Sulfur colloid scan



In-111 labeled platelet scan, or damaged RBD scan. This usually averts a biopsy to confirm the diagnosis.