Ablative therapy has recently emerged as an option for the treatment of small renal masses (SRMs). Benign tumors and indolent renal cell carcinoma (RCC) represent a majority of these masses, although an additional but often unappreciated consideration is upper tract urothelial carcinoma (UC). We report the case of a 74-year-old man with upper tract UC presenting as a SRM without any apparent involvement of the pelvicalyceal system, leading to its inadvertent cryoablation. We also discuss the role of renal biopsy in the management of SRMs undergoing an ablative procedure.