[Benign retroperitoneal schwannoma: a case report and review of the literature].

Retroperitoneal schwannoma is a very rare benign tumour that accounts for only a small percentage of retroperitoneal tumours. The preoperative diagnosis is difficult and the only treatment is complete surgical excision. The authors report their experience with a case of a voluminous retroperitoneal mass in a 42-year- old male patient, incidentally discovered during a diagnostic search for a blunt abdominal trauma. Because of the unclear origin of this mass, the patient underwent periodic radiological and ultrasonographic examinations. Three years later, owing to a slight increase in this mass and vague abdominal discomfort reported by the patient, surgical excision was performed. Histological examination of the surgical specimen revealed an "ancient schwannoma". The patient is alive and well and has had no recurrence in the twenty months since surgery. The authors, after a short discussion of the subject, go on to examine the diagnostic and therapeutic treatments of this rare benign neoplasm, which always arouses lively clinical and scientific interest.