Lung cancer remains the leading cause of cancer-related mortality worldwide, with most patients diagnosed at a metastatic stage. The common metastatic sites include the brain, bone, adrenal glands, and liver. Advances in molecular profiling and the introduction of targeted therapies and immune checkpoint inhibitors have improved survival, leading to the occurrence of metastases in uncommon sites such as the small bowel. Small-bowel metastases from lung cancer are extremely rare and often present with nonspecific symptoms like anemia or abdominal pain, causing delayed diagnosis. These patients may develop life-threatening complications, including obstruction, perforation, or bleeding, requiring urgent surgery.
In this paper, we report two patients with lung cancer who developed symptomatic small-bowel metastases. The first, a 54-year-old woman with metastatic poorly differentiated lung carcinoma, achieved prolonged disease control with chemotherapy and nivolumab but later presented with melena and obstruction. Imaging revealed an ileal mass, and surgical resection confirmed metastasis of poorly differentiated carcinoma consistent with pulmonary origin.
The second, a 74-year-old man with SMARCA4-deficient undifferentiated carcinoma, responded partially to chemoimmunotherapy but later developed ileal perforation requiring emergency surgery, which confirmed metastatic spread.
Small-bowel metastases from lung cancer are exceedingly rare but clinically significant. Although prognosis is generally poor, timely surgical intervention integrated with systemic therapy can provide symptom relief and, in selected cases, extend survival. Clinicians should remain alert to the possibility of gastrointestinal metastases in lung cancer patients presenting with abdominal symptoms, as early recognition may be lifesaving.