A 43-year-old man, active smoker of about 15 cigarettes a day. He came to the emergency department with continuous epigastric pain of sudden onset accompanied by nausea and dizziness. Normal bowel habits. She reported similar episodes of lesser intensity that she related to ingestion and that subsided with fasting. Asthenia and moderate anorexia, with weight loss of about 15 kg in the last three months. On examination she was afebrile, BP 80/40, cutaneous-mucosal pallor and the abdomen was soft, depressible, without defence or signs of peritoneal irritation, although painful on palpation in the epigastrium with discreetly increased peristalsis. The CBC showed a Ht° of 30% with a Hb of 11.1 g/dl, the rest being normal. The abdominal X-ray showed dilated jejunal loops with hydroaerial levels. Abdominal ultrasound revealed a "pseudorenon or sandwich" image in the sagittal view and a "bull's eye or doughnut" image in the axial view. The inner layer was hyperechoic and the outer layer hypoechoic, suspicious of intestinal invagination. Surgical intervention was decided and after anaesthetic induction an abdominal mass located in the mesogastrium was palpated, smooth and mobile. A supraumbilical laparotomy was performed, revealing an intussusception of a jejunal loop that was impossible to reduce, so segmental resection of 30 cm of jejunum was performed, containing a tumour measuring 4 x 4 x 2.5 cm that was reported as anaplastic carcinoma, with a rhabdoid phenotype that invaded the entire wall and infiltrated the subserosal layer. Immunohistochemistry showed high positivity for cytokeratins AE-1/AE-3, cytokeratin 7, cytokeratins 5/6/8/18 and vimentin. Cytokeratin 20, CD-30, CD-31, actin, desmin, CD-117, MELAN-A/M arp-1 and TTF-1 were negative, suggesting a pulmonary origin.

Chest CT confirmed the presence of a right hilar mass of about 4 cm, polylobulated and with spiculated contours, encompassing the upper lobar bronchus but without significant stenosis. Bronchoscopy revealed a thickening of the carina at its separation from the right upper lobar bronchus, with endobronchial tumour that prevented passage of the bronchoscope to the posterior segment. Biopsy confirmed the diagnosis of an undifferentiated carcinoma with the same immunohistochemical pattern as the intestinal mass.

The postoperative period was uneventful and the patient was discharged in good clinical condition. She was subsequently treated with carboplatin AUC 5 day 1, and gemcitabine 1250 mg/m2/day days 1 and 8, every 21 days, with partial response after the fourth cycle of chemotherapy. Six months after diagnosis, she was admitted for progressive cognitive deterioration secondary to multiple right frontoparietal brain metastases, and died fifteen days later.