Notes

This patient has typical symptoms of endometriosis, including dysmenorrhea and dyspareunia. In addition, the nodularity along the back of the uterus along the uterosacral ligaments is suggestive of endometriosis. The patient has typical signs of endometriosis which is characterized by the presence of endometrial glands and stroma outside of the uterus.
Oral contraceptives will be the next best choice for this patient. They provide negative feedback to the pituitary-hypothalamic axis which stops stimulation of the ovary resulting in ovarian suppression of sex hormone production, such as estrogen. Since estrogen stimulates endometrial tissue located outside of the endometrium and uterus, endometriosis can be suppressed by OCPs especially when prescribed in a continuous fashion (omit the week of placebo pills resulting in no withdrawal bleed. Danazol is a synthetic androgen used to treat endometriosis, but due to its androgenic side effects (weight gain, increased body hair and acne, and adverse affect on blood lipid levels) it is not usually the first choice of treatment. Laparoscopy is indicated in the patient who fails medical treatment and/or is planning pregnancy in the near future.
A repeat ultrasound is the most appropriate next step, as this is most likely a hemorrhagic cyst which will resolve on its own.
A patient with a known history of endometriosis, who is unable to conceive and has an otherwise negative workup for infertility, benefits from ovarian stimulation with clomiphene citrate, with or without intrauterine insemination.