Differential Diagnosis for Vaginal Introitus Mass
- Single most likely diagnosis
- Bartholin's cyst or abscess: The patient's presentation of a mobile, soft, nontender cystic mass behind the posterior labium majus is consistent with a Bartholin's cyst. The recent increase in size and discomfort with walking or exercising could indicate a possible abscess formation, although the lack of tenderness and fever makes a simple cyst more likely.
- Other Likely diagnoses
- Vaginal or vulvar cyst: Other types of cysts, such as epidermal inclusion cysts, mucous cysts, or Gartner's duct cysts, could present similarly and should be considered in the differential diagnosis.
- Lipoma or other benign soft tissue tumor: Although less common, lipomas or other benign soft tissue tumors could present as a soft, mobile mass in the vulvar region.
- Vulvar or vaginal varicosities: Varicosities in the vulvar or vaginal area could cause a soft, cystic-appearing mass, especially if they become thrombosed.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Malignant tumor (e.g., vulvar cancer, vaginal cancer): Although the patient's age and the characteristics of the mass make malignancy less likely, it is crucial to consider and rule out cancer, especially given the patient's history of an abnormal Pap test.
- Infectious process (e.g., tubo-ovarian abscess, pelvic inflammatory disease): While the patient's presentation does not strongly suggest an infectious process, it is essential to consider and evaluate for signs of infection, particularly given her history of unprotected sex and multiple partners.
- Rare diagnoses
- Hydrocele of the canal of Nuck: A rare condition where a cystic mass forms in the canal of Nuck, which is a remnant of the processus vaginalis in females.
- Vulvar or vaginal endometrioma: Endometriosis can rarely present as a cystic mass in the vulvar or vaginal area, although this is more commonly associated with pelvic endometriosis.