Differential Diagnosis for a 34-year-old Woman with Intermittent Pelvic Pain and Adnexal Mass
- Single most likely diagnosis:
- Ovarian cyst: The presence of a 4-cm, nontender, right adnexal mass, along with the patient's history of intermittent dull pelvic pain that worsens with physical activity, suggests an ovarian cyst. Ovarian cysts are common in women of reproductive age and can cause pelvic pain, especially if they rupture or torsion occurs. The fact that the pain occasionally occurs about a week before menses also supports this diagnosis, as ovarian cysts can be related to the menstrual cycle.
- Other Likely diagnoses:
- Corpus luteum cyst: Similar to ovarian cysts, corpus luteum cysts can cause adnexal masses and pelvic pain, particularly if they rupture or become hemorrhagic.
- Endometrioma: Given the patient's history of crampy abdominal pain during menses and intermittent pelvic pain, endometriosis with an endometrioma (a cyst filled with old blood) is a possible diagnosis. However, endometriomas are typically associated with more severe and chronic pelvic pain.
- Adnexal torsion (partial or intermittent): Although the patient does not have severe pain or nausea, intermittent adnexal torsion could cause the symptoms described, especially if the torsion is partial or intermittent.
- Do Not Miss diagnoses:
- Ectopic pregnancy: Despite the negative urine pregnancy test, ectopic pregnancy must be considered, especially if there's any chance the vasectomy was not successful or if the patient had unprotected intercourse with someone else. Ectopic pregnancy can present with adnexal mass and pelvic pain.
- Ovarian torsion: This is a surgical emergency that can present with sudden onset of severe pelvic pain, but it can also have a more gradual onset. The presence of an adnexal mass increases the risk of torsion.
- Appendicitis: Although the patient does not have the typical symptoms of appendicitis (such as migration of pain to the right lower quadrant, fever, or changes in bowel habits), appendicitis can occasionally present with pelvic pain and must be considered.
- Rare diagnoses:
- Dermoid cyst (mature cystic teratoma): These are benign tumors that can cause adnexal masses and occasionally torsion or rupture, leading to pelvic pain.
- Tubo-ovarian abscess: This would typically present with more severe symptoms, including fever, purulent discharge, and significant pelvic pain, but it's a possibility if the patient has a history of pelvic inflammatory disease (PID) or recent instrumentation.