An unusual presentation of a primary lung adenocarcinoma: A case report

INTRODUCTION AND IMPORTANCE: Lung cancer is one of the most common malignancies worldwide and common sites of metastasis are to brain, liver, adrenal glands, and bones [1]. Metastasis to the gastrointestinal (GI) tract is extremely rare (<1%) and the most common site is the small intestine [5]. CASE PRESENTATION: A 60-year-old female referred for intermittent colicky abdominal pain and diarrhoea, with cross-sectional imaging showing a distal small bowel mass with lymphadenopathy. Malignancy workup revealed an additional mediastinal mass and raised tumour marker carcinoembryonic antigen (CEA). Bronchoscopy confirmed primary lung adenocarcinoma of the mediastinal mass. Given the raised CEA, evolving obstructive symptoms, and concerns for synchronous lung and gastrointestinal primaries, the patient proceeded to have a small bowel resection leading to the diagnosis of a GI lung metastasis. CLINICAL DISCUSSION: If Symptomatic, suggested treatment of lung metastasis to the GI tract is surgical resection. Current evidence suggests that in isolated GI metastases, resection may have a therapeutic benefit and an association with overall survival rate. CONCLUSION: In patients with symptomatic or isolated GI lung metastasis, surgical resection should be considered for treatment and management of metastatic disease. The role of tumour marker CEA in primary lung adenocarcinoma is unclear.