GOSSYPIBOMA.

Gossypiboma is the technical term for a retained surgical sponge. It is derived from the Latin \"gossypium\" (cotton) and the Swahili \"boma\" (place of concealment). The presentation of gossypiboma is variable. The acute presentation typically consists of local inflammatory reaction. If it becomes infected, an abscess forms.

The differential diagnosis in such cases includes post-operative collection, hematoma, and non-foreign body abscess. A delayed presentation, however, may develop months or even years after the initial surgery. Adhesions and encapsulation are common, and the lesion may present as a mass or subacute intestinal obstruction. In these cases, the differential diagnosis typically includes tumor.

The typical appearance of gossypiboma often includes a whirl-like pattern of radiopaque thread on radiographs. (Although in the US and many other countries surgical gauze is manufactured with radiopaque threads that are easily identified on radiographs, this is not the case in all countries.) On ultrasound, the sponge may appear as a brightly echogenic wavy structure within a cystic mass. The pattern of acoustic shadowing changes with the direction of the ultrasound beam.

On CT, gas trapped within the sponge is visible, as are calcifications in the cavity wall (if long-standing); rim enhancement may also be seen. These lesions have variable signal intensity on MR, depending on the amount of fluid and protein. The capsule is typically dark on T1- and T2-weighted images.