There are rare penile cancers known as fibrosarcomas that can present with a thickened scar-like mass in the shaft of the penis. They tend to not involve the tunica jacket of the penis, but rather occur within the vascular tissue of the penis. Physical examination by a doctor can usually make the distinction.
Fibrosarcomas tend to grow whereas Peyronie’s plaques may expand but do not tend to grow into the spongy vascular tissue of the penis. In my experience, which is extensive in seeing patients with Peyronie’s disease over the past 15 years, I have only encountered one fibrosarcoma and this was a patient who was sent to me from out of state for a very large mass within the penis that did not appear like Peyronie’s disease. There are other types of cancers of the penis which may involve the urethra and may be felt along the under surface of the penis extending from the penile tip to the base of the penis. Either way, it is my advice that should you find a lump within the penis that you should have an evaluation either by your primary care physician, or better yet, a urologist.