Gossypibioma is the term applied for a retained surgical sponge. It is derived latin word -gossypium (cotton) and boma (place of concealment).

The presentation is variable. It can vary from acute inflammatory reaction or features of obstruction. If it becomes infected, an abscess may form. A delayed presentation may develop months or years after initial surgery. Adhesions / encapsulations are common. The lesion may present as mass and cause subacute intestinal obstruction.
The typical appearance on sonography is of a bright echogenic structure with cystic areas. The pattern of shadowing changes with direction of beam . On CT, gas trapped the sponge is visible.
Surgical removal is mandatory.