Hello, I am currently in my 34th week of pregnancy, Since few months I have been seeing a dark patch extending from armpit to breast. I stay in USA, I just did not mention to my doctor here thinking that it's a pregnancy symptom but recently I read somewhere that it could be a sign of cancer.I am worried. The dark patch is only on one side. Could you please let me know what it is. There is also a very small protruding (or very small flap) no pain nothing.hope you are going to clear my doubts Thankyou.