The forgotten surgical foreign body.

Instruments and drains left in the abdomen following surgery may be responsible for bizarre and varied complications. The patient may remain asymptomatic for months or even years. Complications include adhesion formation, intestinal obstruction, abscesses, and erosion into the gastrointestinal tract. We report 3 patients in whom retained surgical material eroded into the duodenum and colon, respectively, and produced unusual radiologic findings and complications.