Introduction:
Unlike left sided accessory spleen that are seen in 10-30% of cases at autopsy, cases of right accessory spleens are extremely rare. This congenital body of healthy splenic tissue simulates tumors from neighboring organs and presents a challenge in formulating a differential diagnosis.
Presentation of case:
We present the case of a patient whose CT scan of the abdomen showed a large mass, 11×8cm, arising retro-duodenal and lying just anterior to the right kidney. To the best of our knowledge, this is the only case where the accessory spleen was found retro-duodenal, directly anterior to the kidney and completely separate from the supra-renal gland. The chief complaint of the patient was right upper quadrant pain, radiating to the back, and colicky in nature. The patient was diagnosed with duodenal gastro-intestinal stromal tumor and a retro-peritoneal sarcoma. The mass was removed via a Kocher's incision and immunohistological examination showed that it was a right sided accessory spleen. The patient's left sided spleen appeared normal.
Discussion:
Efforts to distinguish an accessory spleen from a retroperitoneal tumor with available scans, percutaneous biopsy or biochemical tests are inconclusive. Differential diagnosis between a retroperitoneal tumor and an accessory spleen can only be made after surgical exploration.
Conclusion:
This case highlights the fact that surgeons should consider the possibility of an accessory spleen when making a differential diagnosis of retroperitoneal tumors.