This study aimed to present the atypical clinical presentation and management of a metastatic lung cancer that had spread to an atypical location. Lung cancer is the most common cause of cancer-related mortality worldwide. The brain, liver, adrenal glands and bone are the most common sites of metastatic disease in patients with lung cancer. The reported incidence of symptomatic gastrointestinal metastases is 0.2–0.5%. Early diagnosis should be based on the observation of clinical symptoms and computed tomography (CT) imaging. In the present study, we describe the case of a 43-year-old male with a primary adenocarcinoma of the lung located in the lower right lobe. Following diagnosis, the patient underwent five lines of chemotherapy with a significant tumor reduction. Two years later, a mass located in the sigmoid colon was detected in the patient following a PET/CT scan. The clinical presentation was unusual with vomiting, headache, dyspnea and laboratory hyponatremia. A rare form of metastatic ulcerating adenocarcinoma was identified with colonoscopy, which was confirmed by immunohistochemical findings. A surgical approach was not performed due to the worsening condition of the patient. The patient demonstrated severe anemia and blood hypoxia, and one month later, the patient succumbed to disease. The metastasis may suggest an increase in tumor aggressiveness.