Table 2.

Histological grading of feline mammary tumors

Feature	Grade
Degree of tubule formation
High (>75%)	Well differentiated
Moderate (10–75%)	Moderately differentiated
Little or none (<10%)	Poorly differentiated
Nuclear/cellular pleomorphism
Small, regular, uniform cells/nuclei	Well differentiated
Moderate increase in size and variability	Moderately differentiated
Marked variation in size and variability	Poorly differentiated
Mitotic count (see Table 3)	Well differentiated to poorly differentiated

From Jeglum et al (1985) ⁴⁸