It is difficult to say what may be causing the lump without examination. The lump could be due to an abscess, lipoma or a bony lesion of the sternum. X-ray and CT scan may be required to evaluate the lump and biopsy may be done it the mass is suspicious for malignancy.
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.