Successful Resection of Small Intestinal Stenosis After Treatment With an Immune Checkpoint Inhibitor for Metastatic Lung Cancer in the Small Intestine: A Case Report.

Gastrointestinal (GI) metastases from lung cancer are relatively rare, and their management strategies and outcomes in the era of immune checkpoint inhibitors are unknown. A 59-year-old man with lung cancer was hospitalized. He presented with vomiting due to a small intestinal metastasis. The metastatic lesion reduced in size with pembrolizumab treatment. However, the patient could not feed orally and required continuous central venous nutrition. Following the recurrence of a catheter-related bloodstream infection, the patient underwent small intestinal resection and gastrojejunal bypass surgery. Surgical specimens from the site of intestinal stenosis showed tumor disappearance and inflammatory cell invasion. GI stenosis due to lung cancer metastasis can persist even after effective treatment with immune checkpoint inhibitors. Therefore, surgery for GI metastases should be considered as necessary.