Inflammatory pseudotumors (IPTs) are benign masses arising from nonspecific inflammatory conditions including surgical invasion. We herein report the rare case of an IPT mimicking port-site metastasis in a 69-year-old patient who underwent retroperitoneal robotic partial nephrectomy for stage T1a renal cell carcinoma. Radiological examination performed six months after the surgery revealed the presence of a mass underneath the abdominal wall which coincided with a port site. The tumor was resected by laparoscopic transperitoneal approach, and histological examination led to the diagnosis of an IPT that consists of xanthogranulomatous inflammation. We also discuss the etiology of IPT formation and features distinguishing IPTs from port-site metastasis.