Chronic Intestinal Pseudo-obstruction and Orthostatic Hypotension Associated with Small Cell Lung Cancer that Improved with Tumor Reduction after Chemoradiotherapy

Abstract

Chronic intestinal pseudo-obstruction (CIPO) is a rare disease with symptoms of ileus without obstruction. Most cases of CIPO are idiopathic, and CIPO as a paraneoplastic neurological syndrome (PNS) associated with small cell lung cancer (SCLC) is rare. A 63-year-old man was diagnosed with functional ileus and confined to bed due to orthostatic hypotension. Chest computed tomography revealed a right hilar mass suspected of being lung cancer. Based on detailed examinations, he was diagnosed with limited-stage SCLC. His symptoms were confirmed as PNS because his serum anti-Hu antibody was positive. His PNS was improved with complete tumor reduction by chemoradiotherapy.

Keywords: anti-Hu antibody; chronic intestinal pseudo-obstruction; orthostatic hypotension; paraneoplastic neurological syndrome; small cell lung cancer.

Figure 1.

A chest radiograph taken at the patient’s admission to our hospital showed swelling of the right hilum and scattered ground-glass opacity.

Figure 2.

A chest CT scan on admission showed a 30-mm right hilar mass.

Figure 3.

An abdominal CT scan on admission showed intestinal dilatation with air-fluid levels.

Figure 4.

The treatment regimen and changes in the levels of tumor markers and serum albumin, orthostatic hypotension, and the amount of oral intake. The amount of oral intake increased gradually with tumor reduction, and the orthostatic hypotension was also improved.

Figure 5.

Two courses of chemotherapy and radiotherapy resulted in a complete response of the tumor. There has been no sign of recurrence for more than 12 months after the initial treatment.