[Duodenal bleeding due to metastasis from lung adenocarcinoma controlled by radiotherapy: A case report and literature review].

Introduction: Gastrointestinal (GI) metastases in lung cancer rarely occur.

Case Report: We report here the case of a 43-year-old male active smoker who was admitted to our hospital for cough, abdominal pain and melena. Initial investigations revealed poorly differentiated adenocarcinoma of the superior-right lobe of the lung: positive for thyroid transcription factor-1 and negative for protein p40 and for antigen CD56, with peritoneal, adrenal and cerebral metastasis, as well as anemia requiring major transfusion support. Over 50% of cells were positive for PDL-1, and ALK gene rearrangement was detected. GI endoscopy showed a large ulcerated nodular lesion of the genu superius with active intermittent bleeding, as well as an undifferentiated carcinoma with positivity for CK AE1/AE3 and TTF-1, and negativity for CD117, corresponding to metastatic invasion originating from lung carcinoma. Palliative immunotherapy with pembrolizumab was proposed, followed by targeted therapy with brigatinib. Gastrointestinal bleeding was controlled with a single 8Gy dose of haemostatic radiotherapy.

Conclusion: GI metastases are rare in lung cancer and present nonspecific symptoms and signs but no characteristic endoscopic features. GI bleeding is a common revelatory complication. Pathological and immunohistological findings are critical to diagnosis. Local treatment is usually guided by the occurrence of complications. In addition to surgery and systemic therapies, palliative radiotherapy may contribute to bleeding control. However, it must be used cautiously, given a present-day lack of evidence and the pronounced radiosensitivity of certain gastrointestinal tract segments.