<b><i>Introduction:</i></b> Management of patients with atypical urinary cytology (class III) of the upper urinary tract is often complicated because some patients develop upper urinary tract urothelial carcinoma (UTUC). Here, we aimed to help define the optimal management of these patients. <b><i>Methods:</i></b> We investigated 31 patients who underwent retrograde ureteropyelography (RP) and were diagnosed with atypical findings of upper urinary tract cytology. <b><i>Results:</i></b> UTUC was

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... revealed in 17 of 31 patients during the follow-up period of 1 year or longer. Tumor-like lesions and wall thickening in the upper urinary tract on initial computed tomography (CT) were significant predictors of UTUC (<i>p</i> = 0.0002 and <i>p</i> = 0.012, respectively). All 11 patients with tumor-like lesions and 3 of 8 patients with wall thickening on initial CT underwent nephroureterectomy, and UTUC was confirmed histologically. Moreover, 3 of 12 patients with hydronephrosis only or with normal findings later went on to develop UTUC. Repeated RP performed within 6 months from the initial RP was able to distinguish patients with UTUC from those without, even in individuals with normal CT findings. <b><i>Discussion/Conclusion:</i></b> Repeated RP based on initial CT findings is recommended in patients with atypical urinary cytology of the upper urinary tract. Nephroureterectomy without repeated RP may be warranted in patients with tumor-like lesions on initial CT findings.