I would suggest an ultrasound to evaluate the anatomy to ensure there isn't any abnormality. One consideration may be Peyronie's disease, which can manifest with plaques under the skin of the penis. Again, an ultrasound can be done for further evaluation. I would also suggest a urology referral.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b