[Benign presacral schwannoma producing obstructive uropathy. Clinical case and review of the literature].

We report a case of a presacral benign schwannoma which causes right hydroureteronephrosis without other clinical findings. After a fine-needle aspiration (FNA) biopsy under computed tomography (CT) guidance, a fusocellular tumour without athypia was demonstrated. With the initial diagnosis of benign schwannoma the patient was operated on, removing the tumour, and with the immunohistochemical examination (reactivity for S-100) this diagnosis was confirmed.