Which of the following tumours metastases to heart?
**Core Concept**
Direct cardiac metastasis is a rare phenomenon, usually associated with advanced malignancies. Tumors metastasizing to the heart may cause pericardial effusion, cardiac tamponade, or even atrial myxoma-like lesions. The most common primary sites for cardiac metastasis are lung, breast, and melanoma.
**Why the Correct Answer is Right**
Lung cancer, particularly small cell carcinoma and adenocarcinoma, frequently metastasizes to the heart. The metastatic cells may infiltrate the myocardium, pericardium, or endocardium, leading to cardiac dysfunction. The high vascularity of the lung primary site and the rich blood supply to the heart contribute to this phenomenon.
**Why Each Wrong Option is Incorrect**
**Option A:** Breast cancer is more likely to metastasize to the lungs, bones, and liver, rather than the heart.
**Option B:** Melanoma can metastasize to the heart, but it is less common compared to lung cancer.
**Option C:** Colorectal cancer primarily metastasizes to the liver, lungs, and peritoneum.
**Clinical Pearl / High-Yield Fact**
Remember that cardiac metastasis is a rare but critical differential diagnosis for pericardial effusion, especially in patients with a known history of lung cancer.
**Correct Answer: C. Melanoma