A woman treated for infertility presents with 6-week amenorrhea with urinary retention. The most likely etiology is:
**Core Concept**
The patient's presentation of amenorrhea and urinary retention suggests a condition affecting the pelvic region, likely involving the reproductive system and the urinary tract. This scenario is often associated with an ovarian cyst, particularly a corpus luteum cyst, which can cause these symptoms due to its size and location.
**Why the Correct Answer is Right**
The corpus luteum cyst is a type of functional ovarian cyst that arises from the corpus luteum, a temporary endocrine structure in the ovary that forms after ovulation. As it grows, the cyst can compress adjacent structures, leading to urinary retention and amenorrhea. The increased size of the cyst also causes the ovary to be pushed upward, which can disrupt the normal menstrual cycle.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** Ovarian torsion is a possible complication of a large ovarian cyst but would more likely present with acute abdominal pain and possibly vomiting, not urinary retention.
* **Option C:** Endometriosis is a condition where tissue similar to the lining of the uterus grows outside of it, but it would not typically cause urinary retention or amenorrhea.
* **Option D:** Uterine fibroids can cause pelvic pressure and menstrual irregularities, but they are less likely to cause urinary retention.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that a corpus luteum cyst can be a cause of urinary retention in a woman with amenorrhea, especially if she has a history of infertility. A thorough pelvic examination and imaging studies, such as ultrasound, are necessary to diagnose this condition.
**Correct Answer:** C. Ovarian cyst (most likely corpus luteum cyst).