Growths in the armpits can be benign or they can be be a sign of a serious underlying medical conditions. The physicians who will be well qualified to discuss this issue with you include your internal medicine doctor
Skin outgrowths, known as skin tags, are common findings in the armpit. They are fleshy and painless growths which are benign.
However, it does not sound like the growth you have discovered is a skin tag. If the growth appears deeper within the skin and has the consistency of a gland, then it is most likely a enlarged lymph node.
There are several reasons to have an enlarged lymph node. For example, infections of the skin or other structures in the arm will drain to the lymph nodes of the armpit and may cause them to enlarge. At times, and very importantly, sometimes an enlarged lymph node is a sign of a lymphoma
, which is a type of a blood cancer. It can also be a sign of a body-wide infection, such as HIV or tuberculosis.
As always, however, the diagnosis and management of your specific complaint will require a physical examination by your personal physician. Scheduling a visit with your internal medicine physician as soon as possible is strongly recommended.