Table 2. Clinicopathological classification of endocrine tumours of the pancreas.

Well-differentiated endocrine tumour

Benign behaviour: confined to the pancreas, non-angioinvasive, <2 cm in size, ≤2 mitoses and ≤2% Ki-67-positive cells/10 HPF

Uncertain behaviour: confined to the pancreas, ≥2 cm in size, >2% Ki-67 positive cells/10 HPF or angioinvasive, perineural invasion

Well-differentiated endocrine carcinoma

Low grade malignant with gross local invasion and/or metastases

Poorly differentiated endocrine carcinoma, small-cell carcinoma, high grade malignant, >10 mitosis/HPF

HPF, high power fields; Ki-67, antigen/protein that is a proliferation marker.