A retroperitoneal localization of Castleman's disease was characterized by angiolymphoid hyperplasia. This rare disease (58 cases of abdominal localization reported to date) raises a question of nosology. The clinical features are not specific. Localized forms in young patients involve deep lymph nodes and have a good prognosis after complete surgical exeresis. Inversely, the clinical picture is much more aggressive in multiple localizations involving preferentially superficial nodes with associated plasmocyte proliferation. The prognosis is mediocre in these forms. Although transition stages have been described due to the lack of any known aetiology, the question of nosology remains open: should the different forms be separated or identified simply as two pathological forms?