Lung carcinoma with small intestinal metastases and gastrointestinal bleeding: A rare case report.

The occurrence of small intestinal metastases from primary lung cancer is rare. This report documents the case of a 57-year-old male patient initially diagnosed with non-metastatic lung adenocarcinoma, who presented with abdominal pain 6 months later. Postoperative pathological analysis confirmed the final diagnosis to be small intestinal metastasis from primary lung cancer. Thoracoscopic surgery and systemic chemotherapy were the preferred treatment options. However, the lung tumor spread to the small intestine, causing intestinal obstruction. As the patient could not tolerate anti-tumor therapy, only symptomatic treatment was provided. The patient experienced massive gastrointestinal bleeding and died the next day. Although small intestinal metastasis from lung cancer is rare and difficult to diagnose accurately, it should be considered when encountering a patient with lung cancer exhibiting abdominal symptoms and associated imaging findings. At this point, a pathological diagnosis should be performed immediately to determine the nature and source of the tumor. Furthermore, individualized treatment should be conducted in strict accordance with oncology guidelines. Of note, early detection and treatment are critical to ensure favorable outcomes.