Intussusception is a relatively common disease in pediatric age but it is uncommon in adults. We report a case of a 49-year-old male who presented with an acute jejunojejunal intussusception revealed by abdominal pain and vomiting. He underwent an en bloc resection, and pathological findings concluded to a metastasis of a pulmonary combined small cell carcinoma and adenocarcinoma. A subsequent CT scan revealed the primitive mass of the right lung with no evidence of secondary localization. The biopsy was difficult to perform. The patient underwent a pneumonectomy with lymph node dissection confirming the same diagnosis. He made a good recovery from the surgery, and a postoperative chemotherapy was administrated, and he is in remission until this date.