Introduction: The identification of high grade disease and subepithelial connective tissue invasion (pT1 disease) are important prognostic factors which guide treatment options in upper tract urothelial carcinoma (UTUC). We aim to describe and demonstrate our novel en bloc enucleation technique for the endoscopic diagnosis and treatment of upper tract tumors. Methods: We detail the instruments required for this procedure, as well as the surgical technique to perform an en bloc enucleation and specimen removal. Endoscopic video of a 2cm renal pelvis tumor demonstrates all aspects of the technique, and histopathologic slides illustrate the diagnostic information obtained. Results: A ureteral access sheath is inserted distal to the upper tract tumor, and a flexible ureteroscope is used to visualize the extent of upper tract disease and tumor characteristics. A 200mm thulium fiber laser partially ablates the tumor surface to create an edge for tissue biopsy and post-ablation urine cytology. The tumor base is identified and the subepithelial connective tissue is carefully entered with low ablation laser settings. The correct tissue plane is extended by maintaining the ureteroscope in the subepithelial connective tissue and continuing the dissection along the entire width of the tumor base. Once the tumor is enucleated, a Nitinol stone retrieval basket is used to remove the specimen(s) and a ureteral stent is placed. Conclusions: En bloc enucleation is a safe technique that provides extensive histopathologic information in upper tract urothelial carcinoma. In cases where complete enucleation is not feasible, this procedure affords a mechanism for large caliber biopsies, enhancing diagnostic accuracy. This technique can be therapeutic in low grade and stage disease, but also offers a mechanism for large caliber biopsy if complete enucleation cannot be performed. SOURCE OF Funding: None
