My 16 year old son has a hard lump about the size of a baseball under the breast plate on his right side. x-rays at the ER showed an inflammation, and that thus far his heart and lungs are not affected should we be concerned? And what could it possibly be?
HI. This is most probably a condition called Gynecomastia and the best way is to get this operated, removed and subjected to histopathological examination. Although this is usually a bilateral phenomenon, it is not rare to see like this.  Cancer has to be ruled out by doing histopathology of the removed specimen and X-ray has not much role to play in the diagnosis. Radiography in the form of CT scan of the lesion, chest and maxillae is of help.