[Bladder neck cysts: role of transrectal echography].

High frequency probes for transrectal sonography are well tolerated and permit us to study the cervico-urethral unit carefully. We are allowed to single out some rare causes of obstruction, otherwise difficult to diagnose. Bladder neck obstruction secondary to a cyst is one of these. Our case report is about a young patient with complete retention secondary to bladder cyst discovered by transrectal sonography.