Dark rings around nipples in a diabetic can possibly be hematoma or melanoma formation. It is imperative that you may get locally examined by a physician for an accurate diagnosis. The lesion may require a biopsy to rule out melanoma which could e cancerous at this age group.
Please visit your physician.
Wish you good health!
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.