<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been experiencing absence of menstruation along with pelvic pain. I also feel a mass on my vulva and my menstrual periods have become longer and infrequent. What could be wrong with me?  <response>: Based on your symptoms, you may have endometrial cancer. It is important that we run some tests to confirm the diagnosis and determine the best course of treatment. 