Gastric remnant obstruction due to adenocarcinoma after remote Roux-en-Y gastric bypass

Case Discussion

This case provides a grade example of an important consideration when evaluating a gastric bypass patient with acute abdominal pain: evaluate the gastric remnant and pancreaticobiliary limb carefully. 

Because the gastric remnant and pancreaticobiliary (afferent) limb are excluded from the efferent gastrointestinal tract (flow of ingested material), the obstruction will not result in typical vomiting and relief of pressure. Instead, these patients will have worsening, severe abdominal pain as in this case, and can eventually proceed to ischemic necrosis and perforation.

A gastric bypass patient should never have such dilation of the blind-ending stomach as seen in this case, without raising suspicion for obstruction of the afferent loop. In this case, there is thickening and angulation of the gastric antrum which was thought to represent the volvulus of the gastric remnant (see coronal reformats). A mass was not suspected in the initial interpretation. 

At surgery, greater than one hour of adhesiolysis was performed, suggesting adhesions of the cause rather than volvulus. The operative report is quite long but provides a lot of detail and insight into the case. The surgical biopsy was negative for cancer. 

The patient had a venting g-tube placed at surgery and failed clamping, raising the concern for a mass causing the obstruction. Ultrasound-guided biopsy was performed after filling the obstructed stomach with fluid, allowing a clear acoustic window for biopsy of the site of obstruction at the pylorus. Pathology results showed adenocarcinoma as responsible for the obstruction!

It is also important to evaluate for dilation of the duodenum and proximal jejunum to the jejunojejunostomy, as small bowel stricture or volvulus distally could also occur (afferent loop syndrome). These areas are normal in this case.