Adenocarcinoma of the prostate affects up to 70 % of men over 80 and is the second leading cause of cancer related death in men. We reported an unusual case of a giant prostatic adenocarcinoma compressing bilaterally the 2 external and internal iliac veins that was revealed by a bilateral edema of the lower limbs after histological confirmation the patient was treated by radiotherapy and hormone therapy with a clinical amelioration.