grading: differentiation

Figures evolve 16.7 & 16.8 ).

For most of the common tumours, the pathologist divides them into descriptive categories: well differentiated, moderately differentiated and poorly differentiated. Undifferentiated tumours lack sufficient features to allow more than a broad classification, as do anaplastic tumours (see below under Classification of neoplasms) (Figure evolve 16.9 ).