Background: Retroperitoneal paraganglioma is a rare tumor that develops from chromaffin cells that secrete catecholamines in the sympathetic ganglia. Universally known as pheochromocytoma, tumors located outside the adrenal gland have been designated as extraadrenal paragangliomas. Aim of the work: The authors report the case of a retroperitoneal paraganglioma with analysis of clinical and imaging features and review of the relevant literature. Case report: We report the case of 84-year-old woman with medical history of hypertension and who was complaining of vomiting and pain in the epigastrum and upper right quadrant. Physical examination and laboratory tests revealed no abnormalities. Ultrasound sonography and abdominal CT-scan showed a round well limited retroperitoneal lesion of c. 7 cm composed of cysts and plain tissue adjacent to the tail of the pancreas, the posterior surface of the stomach and the left renal vein. The Magnetic resonance Imaging (MRI) showed a lesion that was hypointense on T1 and heterogeneous hyperintense on T2. The preoperative diagnosis was tumor of the tail of the pancreas or the gastrointestinal stromal tumor (GIST) or the extra digestive stromal tumor (E-GIST). The patient was operated on via a midline incision. We had found a lesion - that was deeply embedded in the left transverse mesocolon near the duodeno-jejunal flexure. It was well encapsulated, surrounded by several peri-capsular veins having connection with the inferior mesenteric vein and the left renal vein. A complete tumor resection was performed.. The histopathological diagnosis was retroperitoneal paraganglioma without any signs of malignancy. Conclusion: When confronted to a posterior abdominal mass, the first step is to be sure of its retroperitoneal origin. Then, the second step is to try to guess its nature and characterize it. When symptoms and signs are not clear, it is essential to know their most frequent location, in order to think of the diagnosis of paraganglioma. Surgery is the main treatment because of their malignant potential. The removal must be complete to be curative.