[Retroperitoneal non-secreting paraganglioma].
Paraganglioma is a rare tumor arising from indifferentiated cells of the primitive neural crest. These tumors are most commonly found in the adrenal gland but other localisations are possible. We described a 60-year-old men with a right retro-peritoneal mass discovered on ultrasound examination. This tumor had an heterogeneous appearance on i.v. contrast injected CT (computed tomography) and MR (magnetic resonance) images. Plasma and urinary catecholamines were normal. This tumor was surgically removed. Immunohistochemical analyses revealed that the tumor cells were strongly positive for neurone specific enolase and chromogranin A. Histopathologic examination diagnosed a non secreting paraganglioma in the right retroperitoneum. After surgery, the patient remained asymptomatic without treatment.