Abstract
The management of urothelial carcinoma has evolved with the introduction of minimally invasive techniques such as laparoscopic or robotic procedures, challenging the traditional approach of open surgery, and giving rise to atypical recurrences (ARs). ARs include port-site metastasis and peritoneal carcinomatosis, yet discrepancies persist among authors regarding their precise classification. Incidence rates of ARs vary widely across studies, ranging from less than 1% to over 10% in both muscle-invasive bladder cancer (MIBC) and upper tract urothelial tumor (UTUC). Peritoneal metastases predominate as the most common ARs in patients with MIBC, while retroperitoneal metastases are prevalent in those with UTUC due to differing surgical approaches. The timing of AR presentation and survival outcomes closely mirror those of conventional recurrences, with which they are frequently associated. Pneumoperitoneum has progressively been regarded less as the cause of ARs, while surgical-related risk factors have gained prominence. Current major surgical-related causes include tumor spillage and urinary tract violation during surgery, avoidance of endo bag use for specimen extraction, and low surgical experience. Factors such as tumor stage, histological variants, and lympho-vascular invasion correlate with the risk of ARs, suggesting a close association with tumor biology. Further studies are required to better understand the incidence, risk factors, characteristics, and outcomes of ARs.