A 45-year-old woman presents with sudden attacks of wheezing, shoness of breath, episodic hot flashes, abdominal cramps and diarrhea. Physical examination shows facial redness, as well as hepatomegaly and pitting edema of the lower legs. A 24-hour urine specimen reveals elevated levels of 5-hydroxyindoleacetic acid (5-HIAA). A CT scan of the abdomen demonstrates multiple 2- to 3-cm nodules throughout the liver and a 2-cm nodule in the jejunum. An echocardiogram would be most expected to demonstrate which of the following?

**Core Concept**
The patient's presentation is suggestive of carcinoid syndrome, a condition caused by the inappropriate secretion of serotonin (5-HT) and other vasoactive peptides by a carcinoid tumor. This syndrome is characterized by flushing, diarrhea, wheezing, and cardiac abnormalities due to serotonin's effects on the heart and blood vessels.

**Why the Correct Answer is Right**
The echocardiogram would be expected to show right ventricular (RV) hypertrophy and/or dilatation due to the chronic effects of serotonin on the heart. Serotonin causes vasoconstriction, which increases the resistance against which the right ventricle must pump blood. This leads to RV hypertrophy and/or dilatation as the heart adapts to the increased workload.

**Why Each Wrong Option is Incorrect**
**Option A:** Left ventricular (LV) hypertrophy is not a characteristic finding in carcinoid syndrome. The primary effect of serotonin on the heart is on the right ventricle.
**Option B:** Tricuspid regurgitation may be present due to the effects of serotonin on the tricuspid valve, but it is not the most expected finding.
**Option C:** Pulmonary arterial hypertension is a possible complication of carcinoid syndrome, but it is not the most direct effect of serotonin on the heart.

**Clinical Pearl / High-Yield Fact**
Carcinoid syndrome is a classic example of a paraneoplastic syndrome, where a tumor (in this case, a carcinoid tumor) secretes substances that cause systemic effects, even in the absence of direct invasion or metastasis.

**Correct Answer:** C. Right ventricular hypertrophy.

✓ Correct Answer: D. Pulmonic stenosis