Desmoplastic tumours with divergent differentiation are principally located in the abdomen and develop locally or regionally. They occur in adolescents or young adults and are characterized at histology by a proliferation of undifferentiated small cells surrounded by a dense stroma. Only immuno-histo-chemistry provides the diagnosis. Since their chemosensitivity is rare and often partial the outcome is usually lethal. Six new cases of this recently described entity are presented here. The authors are in favour of a multidisciplinary and aggressive management, combining intensive polychemotherapy, extensive surgical exerisis and total abdominal radiotherapy.