Malignancy in the male breast is relatively very rare,but it could happen especially to much older men.
Several causes can produce a lump in males and it doesn't mean that it is cancer related.However an investigations needs to be done particularly if the lump is painless.
This lump could be due to many causes,like an infection, cyst etc.
Certain medications, steroid supplement and marijuana use, have been linked to Gynecomastia which can present with enlarged breasts or a lump under one or both areolas.
Gynecomastia is breast development that occurs mainly in young males,but It can happen at any age and for a number of different reasons.Older men may have an underlying medical condition that requires investigation and treatment.
It's impossible to tell you over the internet what this lump could really be. Your doctor will examine you and probably order a few tests if you insist on having them.If he/she tells you to "wait and see" then find another doctor,preferably a Breast Specialist who will order the tests.The results of these test will let you and the doctor know if a biopsy is needed. If you are taking any medication,make sure you mention it to your doctor.
Hoping that it's nothing serious.
Take care and best wishes...