**Correct Answer: D. Angiitis**

**Core Concept:** Corpus Cancer syndrome is a clinical entity characterized by the triad of metrorrhagia, anemia, and elevated serum pregnancy hormone levels in a postmenopausal woman. This condition is caused by a hormonal imbalance resulting from an ectopic production of hCG (human chorionic gonadotropin) by a corpus luteum tumor, also known as a corpus cancer.

**Why the Correct Answer is Right:** Corpus cancer is a rare tumor of the corpus uteri (uterine corpus), which produces hCG. This leads to the characteristic triad of symptoms: metrorrhagia (menstrual bleeding outside of the normal menstrual cycle), anemia due to excessive blood loss, and elevated serum pregnancy hormone levels.

**Why Each Wrong Option is Incorrect:**

A. **Angiitis (vasculitis)** is an inflammatory condition affecting blood vessels, not a tumor or hormonal imbalance. It is unrelated to Corpus Cancer syndrome.

B. **Endometrial cancer** is a different type of tumor affecting the endometrium (lining of the uterus), not the corpus (body of the uterus) like Corpus Cancer syndrome.

C. **Uterine fibroids** are benign tumors of the smooth muscle cells in the uterine walls and do not involve the corpus luteum. They are unrelated to Corpus Cancer syndrome.

**Clinical Pearl:** Corpus Cancer syndrome is a unique condition that should be considered in the differential diagnosis of postmenopausal bleeding and elevated serum pregnancy hormone levels, especially in the absence of other common causes like endometrial or cervical cancer. Rapidly increasing serum hCG levels can indicate a more aggressive presentation, and prompt surgical intervention may be necessary for definitive diagnosis and treatment.