Review Question - QID 211097

A 43-year-old woman presents to the clinic complaining of “spotting.” She states that over the past 5 months she has had intermenstrual bleeding. Additionally, her menses last more than a week with the first 4 days consisting of heavy bleeding. She denies abdominal pain but reports feeling an increasing “pressure-like" discomfort. She denies dysuria, dyspareunia, or dyschezia. Prior to 5 months ago, her menstrual periods were only 4 days long and consisted of moderate bleeding. Her periods normally occur every 28 days. She is frustrated because she feels like she needs to wear a pad all the time. The patient delivered 3 healthy children vaginally without complications, followed by a tubal ligation. Her last menstrual period was 1 week ago. She is sexually active with her husband and denies a history of sexually transmitted diseases. She has never had an abnormal pap smear. Her last pap smear and test for human papillomavirus was 4 years ago. The patient has hypothyroidism treated with levothyroxine. Her temperature is 98.7°F (37°C), blood pressure is 112/71 mmHg, pulse is 81/min, respirations are 12/min, and oxygen saturation is 98% on room air. On physical examination, the thyroid is normal in size without masses or tenderness. Pelvic examination reveals a firm, mobile, enlarged, irregularly-shaped uterus without adnexal tenderness. Speculum exam is unremarkable. Which of the following is the most likely diagnosis?