There exist rare cases in which a prostatic carcinoma invades the peri
rectal space producing an extrinsic rectal stenosis. Three cases are d
iscussed. Differential diagnosis with a rectal tumor is difficult clin
ically, but endorectal ultrasound and deep rectal biopsies must provid
e the correct diagnosis in most cases. Hormonotherapy is recommanded,
but prognosis is reserved.