Which site is most commonly involved by metastasis in Wilms tumor?

Which site is most commonly involved by metastasis in Wilms tumor?

• A. Lungs
• B. Liver
• C. Bones
• D. Brain

Answer: (A)

Wilms tumor most commonly spreads to the lungs. The tumor tends to disseminate via the bloodstream, and the lungs are the first major organ filter encountered by circulating tumor cells in children, making pulmonary metastases the most frequent distant site. On imaging, these metastases appear as pulmonary nodules or infiltrates. The liver is the next most common site, but bones and brain metastases are much less common, especially at initial presentation. This pattern also aligns with stage IV disease when the lungs are involved, guiding multimodal treatment plans.

Wilms tumor most commonly spreads to the lungs. The tumor tends to disseminate via the bloodstream, and the lungs are the first major organ filter encountered by circulating tumor cells in children, making pulmonary metastases the most frequent distant site. On imaging, these metastases appear as pulmonary nodules or infiltrates. The liver is the next most common site, but bones and brain metastases are much less common, especially at initial presentation. This pattern also aligns with stage IV disease when the lungs are involved, guiding multimodal treatment plans.