[A case of Oberling's retroperitoneal xanthogranuloma in pilot].

A rare case of retroperitoneal mass identified in the pilot, aged 48, is described. There has been noted the complexity of differential diagnosis between the benign and malignant process associated with the given type of tumor which led to some problems when making an expert decision. The tumor was found to be non-removable, however, considering the good clinical state of the pilot, he was permitted of flying activity which he continues to perform successfully more than 10 years.