Desmoid tumour of the mesentery secondary to colectomy. An exceptional cause of ureteric obstruction.

Desmoid tumours are rare lesions with a local invasive potential and a risk of recurrence, considered to be benign due to the absence of metastases. T hey are classified as fibromatoses and may be associated with Gardner's syn drome. The authors report an unusual case, in a 33-year-old woman, of a des moid tumour invading the right ureter with upper tract dilatation. Etiologi c factors (traumatic, hormonal, auto-immune...) are discussed, together wit h the treatment of choice to lower the risk of recurrence.