Commentary: imaging of islet-cell tumours

Abstract

Neuroendocrine tumours (NETs) are often thought to be rare and rather recherche ´ cancers which are of little concern to the general physician, surgeon or radiologist because of their rarity and esoteric nature. In fact, while relatively uncommon, the total group of gastro-entero-pancreatic (GEP) tumours incorporates the spectrum of all types of carcinoids, including bronchial carcinoids, and the whole gamut of islet-cell tumours. Some of these may present as functioning tumours, with a plethora of hormonal secretions and concomitant clinical syndromes, and GEPs in general have an incidence around 30 per million population per year. This means that in the whole European Union, for example, there will be in the region of 12 000 new patients every year presenting with one or another manifestation of these tumours. Furthermore, the comparatively long survival of many of these patients, compared to more common adenocarcinomas or epithelial tumours, implies that the point prevalence is also not inconsiderable. 1 However, it is undoubtedly true that these tumours can be difficult to identify, especially in their early stages, and it is then that radiological investigation becomes of paramount importance. The preceding chapters outline the relative uses of computed tomography (CT), magnetic resonance (MR), ultrasound, angiography with functional localization and radiopharmaceutical identification of these tumours, each chapter written by an author or authors eminent in their fields. Nevertheless, it is important to relate each imaging modality to other modalities and to assess the relative utility of each in different circumstances. As ever, the answer as to which imaging technique is ‘best’ depends very much on the question that one wishes to be answered.