The pathologic features of poorly differentiated renal cancer cells include significant cellular heterogeneity, rapid growth and invasiveness, and high degree of malignancy. Pathologically, the degree of differentiation is used to describe the degree of similarity between cancer cells and normal cells in terms of cell structure and function. The more similar they are to normal cells, the higher the degree of differentiation is, and conversely, the lower the degree of differentiation is. Hypo-differentiated cancer cells have significant morphological differences from normal cells, including cell size, number of nuclei, number of nucleoli and morphology. Functionally, poorly differentiated cancer cells possess fewer functions of normal cells, and compared with highly differentiated cancer cells, poorly differentiated cancer cells proliferate faster, have a stronger invasive ability, and have a higher degree of malignancy.