Jejunal Adenocarcinoma with Pulmonary Hilar Lymph Node Metastasis Initially Misdiagnosed as Pulmonary Hilar and Mediastinal Tumors.

Introduction: Pulmonary metastases from small intestinal cancers are rare. This report describes a case of jejunal adenocarcinoma with metastasis to hilar lymph nodes. Case Description: This case report presents the medical history of a 60-year-old male who sought medical attention for symptoms of fatigue and night sweats. Fiberoptic bronchoscopy revealed metastatic malignant tumors in the hilar lymph nodes. The patient underwent six cycles of etoposide + cisplatin chemotherapy combined with atezolizumab immunotherapy. During treatment, the patient developed symptoms of hemoptysis and melena. Further evaluation using small bowel endoscopy revealed a malignant tumor in the jejunum. Conclusion: Small intestinal adenocarcinoma with pulmonary metastasis is rare and is associated with poor prognosis. This case underscores the importance of considering the small intestinal origin when evaluating pulmonary or mediastinal masses of unknown primary origin.