What happened, in summary

A 55-year-old man was admitted after two months of vomiting and abdominal distention, accompanied by weight loss. Imaging showed dilation of the lower duodenum and upper jejunum without a mechanical blockage. The same abdominal CT unexpectedly captured a 43 mm mass in the lower right lung and enlarged lymph nodes above the clavicle. Further imaging found no metastases in the brain, liver, kidneys, or bones.

He was diagnosed with right lung adenocarcinoma classified as cT2aN3M0 stage IIIB. The bowel symptoms were attributed to chronic intestinal pseudo-obstruction caused by a paraneoplastic neurologic process. He also had markedly elevated alkaline phosphatase and other biliary enzymes without liver metastasis or biliary obstruction, leading to a diagnosis of Stauffer syndrome as a second paraneoplastic complication.

He received three courses of chemotherapy. The intestinal pseudo-obstruction began to improve after 15 days. With continued treatment, the biliary enzyme abnormalities gradually decreased and the lung tumor became smaller, representing a partial response. He was discharged two months after admission and continued outpatient follow-up. In this case, treatment of the lung cancer also relieved two unusual systemic syndromes that had been responsible for his initial gastrointestinal and liver-related presentation.