Tumours of the endocrine pancreas are rare entities with evidence of endocr
ine cell differentiation. Immunohistochemistry is the most reliable method
used to study such tumours either for the identification of their hormonal
product(s) or to explore functional aspects like proliferative activity or
oncoprotein overexpression (e.g. p53). Most of the endocrine tumours of the
pancreas are well differentiated and behave as benign or low grade maligna
nt tumours. Poorly differentiated (small cell) endocrine carcinomas are rar
e and have a poor prognosis.