[Supernumerary spleen simulating a renal tumor. Case report].

Objective: Report one case of ectopic spleen simulating a renal tumor. We performed a review of etiopathogenesis, diagnosis and treatment.

Methods: We present the case of a 54-year-old splenectomized female patient with the incidental diagnosis on ultrasound of a left kidney upper pole mass simulating a renal tumor.

Results: After the performance of CT scan, and with the suspicion of renal neoplasia, the patient underwent tumorectomy with the pathologic diagnosis of the specimen compatible with supernumerary spleen.

Conclusions: We emphasize the importance of including pseudo masses of splenic origin in the differential diagnosis of left renal, adrenal and retroperitoneal tumors. We emphasize the importance of CT scan as the imaging test of choice, and gammagraphy as a complementary test. We point out conservative attitude as the most suitable in cases of asymptomatic pseudomass of splenic origin.