Tumor staging of prostate cancer is a fundamental principle in management and therapy, with a hallmark being tumor growth beyond the organ boundary. Often, this is referred to as “capsule penetration”, suggesting the existence of a true prostatic capsule that would facilitate the determination of tumor penetration. In fact, the prostate does not have a true capsule and, depending on the anatomic area, it blends with the surrounding fibrous, adipose and muscular tissue. This makes it sometimes difficult or impossible to unequivocally identify extraprostatic tumor extension. It is necessary to appreciate this difficulty in order to better understand the significance of extraprostatic tumor extension.