A 55-year-old woman presents to the neurology clinic with new-onset headaches, confusion, and weakness in her left arm. An MRI of the brain reveals multiple lesions suggestive of metastasis. The medical team investigates to determine the primary site of the cancer.
Secondary metastasis to the brain most commonly occurs when the primary site of neoplasm is in:
A. Liver
B. Lung
C. Breast
D. Kidney
Answer:
The Correct Answer is: B. Lung
Explanation:
Lung (B):
– The lungs are the most common primary site for metastatic brain tumors. Lung cancer, particularly small cell lung carcinoma and non-small cell lung carcinoma, frequently spreads to the brain.
– The brain is a common site for lung cancer metastases due to the rich blood supply and the ability of lung cancer cells to travel through the bloodstream to distant sites.
Explanation of Incorrect Options:
Liver (A):
– While the liver is a common site for metastases from various primary cancers, liver cancer itself does not commonly metastasize to the brain. The most frequent metastatic sites for liver cancer are the lungs and bones.
Breast (C):
– Breast cancer is also a common primary cancer that can metastasize to the brain, but it is less common than lung cancer in this context. When breast cancer metastasizes, it often spreads to the bones, liver, and lungs before the brain.
Kidney (D):
– Kidney cancer (renal cell carcinoma) can metastasize to the brain, but it is not as common as metastases from lung or breast cancers. The typical metastatic sites for kidney cancer include the lungs, bones, and liver.
In conclusion, secondary metastasis to the brain most commonly occurs when the primary site of neoplasm is in the lungs, making option B the correct answer.