[Splenosis simulating a renal mass].

Objective: To report a case of splenosis and to review its diagnosis and treatment in the related literature.

Method: We report the case of an asymptomatic 49-year-old man with splenectomy performed when he was 22. Lumbo-sacral MRI showed a left perirenal mass probably with renal origin.

Results: CT scan ruled out the renal origin. Due to previous splenectomy, splenosis was suspected. 99mTc-labeled heat-damaged erythrocytes scan confirmed the diagnosis. No treatment was applied.

Conclusions: Clinicians should be aware that unknown origin masses, mainly in the peritoneal cavity, with a history of previous splenic trauma or splenectomy, might represent splenosis. A non-invasive diagnosis can be achieved with 99mTc-sulphur colloid scan, 99mTc-labeled heat-damaged erythrocytes or ferrumoxide-enhanced MRI, thus avoiding unnecessary surgical explorations.