Ectopic splenic tissue can be found as congenital or acquired condition. It is occasionally symptomatic and very rarely can simulate a neoplastic disease, especially when it locates in the retroperitoneal space. A case of ectopic splenic tissue simulating a retroperitoneal tumor is reported. A 32-years-old female was admitted in the clinic for a tumor in the left retroperitoneal space, discovered by ultrasound and computed tomography. 9 years before, an operation for a pheochromocytoma with similar localization was performed as the tumor was removed together with the spleen. At this admission, the tumor was considered a local recurrence of the pheochromocytoma and was resected. The result of the histopathological examination showed a splenic tissue.