Prognostic and immunohistochemical validation of the Capella classification of pancreatic neuroendocrine tumours: an analysis of 82 sporadic cases

Aims: To study the clinical outcome of 82 cases of pancreatic neuroendocrine tumours classified according to the recent histological and prognostic classification of Capella. Methods and results: Eighty-two surgical cases of pancreatic neuroendocrine tumours were examined histologically with immunohistochemical staining of paraffin sections using streptavidin-biotin complex and application of antibodies against chromogranin A and 10 hormonal peptides. Classification in four groups correlated with long follow-up and outcome of these cases. Histological examination showed 30 group I, four group II, 41 group III and seven group IV tumours. Twenty-one (70%) of group I tumours were insulinomas, whereas 25% of group III tumours were glucagonomas and 25% were unclassified. Most group IV tumours were unclassified, showing no immunohistochemical staining with any of the 10 hormonal peptides tested. Outcome was clearly correlated with tumour group. Among the 14 patients who died of the disease, four had group IV and 10 group III tumours. Thus, unclassified asymptomatic tumours without immunohistochemical staining had a poorer prognosis than asymptomatic tumours with staining. Conclusion: This study validates the Capella classification as easy to apply and useful in predicting clinical outcome.