Paraneoplastic intestinal pseudo-obstruction as the presenting feature of small-cell lung cancer

A previously healthy 50-year old man presented with acute small bowel obstruction. No etiology was found at laparotomy. Postoperatively, the patient remained symptomatic with nausea, vomiting and severe constipation. Gastroscopy revealed retained food in the stomach. Gastric emptying of solids and liquids was dramatically decreased at scintigraphy. The colon was dilated on X-ray study. Chest X-ray revealed a pneumopathy and a small-cell lung cancer was discovered at bronchoscopy. The patient died 5 months after onset. Histologic study of the gut showed widespread degeneration of the myenteric plexus with plasma cell infiltration, Schwann cell proliferation and a reduced number of neurons of which many were abnormal. Intestinal pseudo-obstruction can reveal a small-cell lung cancer; the mechanism of neuronal impairment leading to pseudo-obstruction remains unknown, but could be related to the pathophysiology of paraneoplastic syndromes.