Investigation of choice in postcoital bleeding in a 60-year-old lady is:
**Core Concept**
Postcoital bleeding in a 60-year-old lady warrants a thorough investigation due to the risk of underlying malignancy, such as endometrial or cervical cancer. The investigation of choice should be able to visualize the entire uterine cavity and cervical canal to detect any abnormalities.
**Why the Correct Answer is Right**
The investigation of choice in this scenario is a **hysteroscopy**. This is because hysteroscopy allows for direct visualization of the uterine cavity and cervical canal, enabling the detection of any abnormalities such as polyps, fibroids, or cancer. A **hysterosalpingogram (HSG)** is also a useful investigation, but it is less sensitive than hysteroscopy for detecting endometrial cancer. **Endometrial biopsy** is a useful investigation for sampling the endometrium, but it does not provide a comprehensive view of the uterine cavity and cervical canal.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not specified, but it could be a colposcopy, which is useful for examining the cervix and vagina, but not the uterine cavity.
**Option B:** This option is not specified, but it could be an ultrasound, which is useful for assessing the size and structure of the uterus, but not for visualizing the cervical canal or detecting cancer.
**Option C:** This option is not specified, but it could be a Pap smear, which is useful for screening for cervical cancer, but not for investigating postcoital bleeding.
**Clinical Pearl / High-Yield Fact**
A high index of suspicion for underlying malignancy is essential in postmenopausal women presenting with postcoital bleeding, and hysteroscopy is the investigation of choice to visualize the entire uterine cavity and cervical canal.
**Correct Answer:** C. Hysteroscopy.