A retained foreign body mimicking colon cancer.

Retained foreign bodies can be a challenging diagnosis due to the wide array of presentations and greatly varied range of time to detection. Here we report a case of a retained surgical sponge detected 5 years postoperatively after an extensive workup for colon cancer. This case demonstrates the novel finding of a retained surgical sponge appearing as colon cancer and serves as a reminder that symptoms that cannot be explained by a standard workup, in any patient who has undergone previous surgery, must have retained surgical instruments as a differential diagnosis.