Fig. 1.

Histopathological findings of papillary urothelial tumors. a Thickness of layers. Each number represents the corresponding score: 0 means a thickness less than seven layers with intact umbrella cells, 1 means a thickness less than seven layers with the loss of umbrella cells, 2 means a thickness more than seven layers with intact umbrella cells, and 3 means a thickness more than seven layers with the loss of umbrella cells. b Mitosis. 1 means a few mitoses less than five per high power field, 2 means mitotic index between five and ten mitoses per ten HPF, and 3 means more than ten mitoses per ten HPF. c Cytologic atypia. 0 Atypia restricted to the surface is not considered true atypia. 1 Diffuse cellular atypia in a random fashion, but with a mild degree is score 1. 2 Diffuse cellular atypia in a random fashion and a moderate to severe degree of atypia is defined score 2