Splenosis presenting as a left renal mass indistinguishable from renal cell carcinoma

Splenosis following splenic trauma is a common but underdiagnosed entity before surgical exploration. In all previously reported cases the ectopic splenic tissue was distinctly separate from the kidney. To our knowledge we report the first known case in which the splenic tissue was located in direct apposition with the kidney. Using conventional imaging techniques, including renal ultrasonography, abdominal computerized tomography and selective renal arteriography, this ectopic splenic tissue appeared to be part of the left kidney and was indistinguishable from renal cell carcinoma. The pathophysiology, clinical presentation and diagnostic studies of splenosis are reviewed.