Abstract
BACKGROUND: Lung cancer is the most prevalent malignant tumor in human body, and is characterized by a high level of malignancy. The most common metastatic sites include the liver, bone, brain, and adrenal gland, while lung cancer resulting in gastrointestinal tract metastasis is uncommon. CASE SUMMARY: A 74-years-old man with lung cancer was hospitalized owing to blood in the stool, The cause was identified as metastasis to the small intestine, and the patient subsequently underwent radical resection of the small intestine tumor. Currently, the overall condition of the patient is good, and undergoing combined chemotherapy. CONCLUSION: Early intervention in patients with metastatic tumors can significantly improve prognosis.