[Benign retroperitoneal schwannoma: report of three cases].

Schwannoma is a tumour arising from Schwann cells. It has a variable presentation and its preoperative diagnosis is difficult. Retroperitoneal schwannoma is an exceptional site. Although the great majority of schwannomas are benign, malignant forms also exist, frequently associated with Von Recklinghausen syndrome (4% of cases) or other neurofibromatoses. The authors report three cases of benign retroperitoneal schwannoma discovered in a context of low back pain, altered bowel habit or incidentally, The frequency, diagnosis, imaging and treatment of this rare tumour are discussed.