Undiagnosed primary lung carcinoma with initial manifestation of intestinal obstruction: A case report and literature review.

Small intestinal metastasis from primary lung carcinoma is infrequent and seen at the terminal stage of the disease as the first sign. These patients are often present as perforation and peritonitis but rarely with small bowel obstruction. We reported a case of a 61-year-old man who was admitted to our hospital with acute abdominal pain. Abdominal X-ray manifested an acute ileus. Ileoileal resection-anastomosis was performed after removal of two separate tumors in the small intestine. Histopathological result indicated metastatic adenocarcinoma. The patient had not been diagnosed as any carcinoma or lung disease previously. The postoperative thorax computed tomography scan showed a lesion at the right lung, which was pathologically defined as adenocarcinoma of the lung by bronchial brushing. This case is reported to arouse a clinical suspicion of intestinal metastasis in undiagnosed primary lung cancer presenting with acute abdominal pain. Early diagnosis and treatments are vital for improving survival of the patients.