Retroperitoneal ancient schwannoma: review of clinico-radiological features.

A case is reported here of an ancient schwannoma in the retroperitoneum. The findings of abdominal ultrasound and CT in a patient with a retroperitoneal ancient schwannoma are presented, and the clinical and radiological features of this unusual tumour are reviewed. The presence of a large, well-delineated complex cystic mass in the deep soft tissues should raise the possibility of an ancient schwannoma. It is important to recognize these tumours as benign with excellent prognosis so as to avoid unnecessary radical surgery.