Perirenal textiloma: MR and serial CT appearance

We describe changes in imaging features of a textiloma (retained surgical sponge or retained foreign body) left in the renal fossa after exploratory renal surgery. One year after the initial surgery, the MR aspect of the textiloma was not specific, with a homogeneous low signal intensity on T1-weighted images. Serial CT examinations over 4 years demonstrated progressive growth and calcification of the mass which appeared pseudocystic with a peripheral inflammatory wall. Granulomas caused by a retained surgical sponge should be considered as a cause of retroperitoneal mass in patients with a history of prior surgery.