<s>[INST] 50 yr old white male, with dark purplish bruise on inside of left arm near armpit, has a white center thats sighltly firm (entire brise is size of 50 cent piece, pear shaped and painless...didnt know it was there till wife noticed it.  Now that Ive touched it I can feel it and if touch it, its slightly painful...barely registers on pain scale though) [/INST] Hello share your concern. Looking at your description it might be related to enlarged lymph node, axillary abscess, sebaceous cyst or local hematoma. If possible please upload me a photograph and provide more information like you are taking any medicine? Is there any history of discharge?relevant medical history. I would advise you to take an appointment with a general surgeon or your family physician as per your convenience for physical examination and further course of action. In case of enlarged lymph node you may require further investigation like CBC, ESR, CRP, liver function test, blood sugar and FNAC if need be. At the same time your doctor should rule out possibility of metastasis by physical examination about which your doctor knows. Hope you will find my answer informative and useful, please feel free to ask for further clarification, I will gladly answer you. Best wishes </s>