Review Question - QID 213413

A 34-year-old woman comes to the gynecologist complaining of vaginal swelling and discomfort. She states that over the past 2 weeks she has noticed swelling of her right labia. The swelling continued to grow in size and now causes her discomfort when walking. She denies abnormal discharge or bleeding from the swelling or from the vulva. She normally shaves the area, but with the recent pain, she has been unable to. She denies any history of known trauma. The patient is relatively healthy and takes only a multivitamin. She never received the vaccine for human papillomavirus (HPV). On physical exam, there is a fluctuant, swelling of the right labia, most prominently at the posterior vestibule. Which of the following is the most likely diagnosis?