84 A rare and complex case of lung adenocarcinoma spreading to the small intestine has been reported, shedding light on the challenges of diagnosing such metastases. A 64-year-old man, previously diagnosed with lung adenocarcinoma and treated with surgery and chemotherapy, presented with gastrointestinal symptoms nearly a year after his lung cancer diagnosis. This case, published in the International Journal of Surgery Case Reports, has emphasised the difficulty in early detection and the potentially life-threatening complications associated with such metastasis. The patient, who had undergone a right upper lobectomy and lymphadenectomy for lung cancer, experienced persistent abdominal pain, fever, and black stools a year after his initial surgery. These symptoms led him to seek medical attention. Initial tests, including a CT scan and capsule endoscopy, revealed a mass in the small intestine, which was later confirmed to be a metastatic tumour from the lung adenocarcinoma. Despite no signs of distant metastasis at the time of his lung surgery, the tumour had spread, presenting a significant challenge for both diagnosis and treatment. Lung cancer remains one of the most lethal forms of cancer, with nearly half of all cases presenting with metastases at the time of diagnosis. However, metastasis to the small intestine is extremely rare, making this case particularly noteworthy. The symptoms of such metastasis are often vague and non-specific, including gastrointestinal bleeding, abdominal pain, and anaemia. In this case, the patient’s gastrointestinal bleeding and anaemia were the first indicators that something was amiss, but it took further investigation to uncover the true cause. The diagnostic process was arduous. Despite multiple imaging tests, including enhanced CT scans and a colonoscopy, the source of the gastrointestinal bleeding remained elusive until capsule endoscopy revealed a mass in the small intestine. Surgery confirmed that the tumour was indeed a metastasis of the patient’s previous lung adenocarcinoma. The mass, measuring 8 by 7 centimetres, was located in the small intestine, approximately 80 centimetres from the ileocecal region, and had adhered to the surrounding intestinal tissue. Pathology tests done after surgery showed that the tumour cells had certain markers that are usually found in lung adenocarcinoma. This confirmed that the cancer had spread from the lungs to the digestive tract, which is very uncommon. This type of metastasis is notoriously difficult to detect early, as symptoms often do not manifest until the cancer has significantly progressed. Moreover, prognosis in such cases is poor, with survival times generally limited after diagnosis of gastrointestinal metastasis. While the surgery was successful in removing the tumour, the patient’s overall prognosis remains guarded. The report highlighted the importance of considering metastasis to the gastrointestinal tract in lung cancer patients who present with gastrointestinal symptoms, especially when they have a history of lung adenocarcinoma. Early detection, although difficult, is crucial for improving outcomes. This case serves as a reminder of the unpredictable nature of cancer metastasis. While the common sites for lung cancer spread include the adrenal glands, bones, and brain, clinicians should remain vigilant for less common metastases, such as those to the gastrointestinal tract.