Gastrointestinal hemorrhage caused by duodenal metastasis from a primary lung adenocarcinoma: A case report.

The present case study reported a rare case of duodenal metastasis from a lung adenocarcinoma. A 62-year-old male, who underwent radical lung cancer surgery two years ago, was readmitted to Guangzhou Red Cross Hospital complaining of epigastric pain. The esophagogastroduodenoscopy identified a 2.5x3.5 cm ulcerative lesion at the duodenum. Histopathological and immunohistochemical staining results confirmed that the lung adenocarcinoma had metastasized to the duodenum. The tumor cells were positive for cytokeratin-7, thyroid transcription factor-1 and napsin-A expression, but negative for caudal-related homeobox 2 expression. Prior to the second cycle of targeted treatment with anlotinib, the patient reported severe hematochezia. Therefore, an angiography and artery embolization were subsequently performed. However, the patient succumbed to acute kidney injury three days after the operation. The metastasis of lung cancer to the gastrointestinal tract is extremely rare and usually asymptomatic. However, when treating patients with lung cancer presenting with digestive symptoms or other distant metastatic sites, clinicians should consider the possibility of gastrointestinal metastasis so that it can be identified in a timely manner. If lesions exist, doctors should locate these and perform biopsies to conduct histopathological and immunohistochemical examinations to make a clear diagnosis.