CT/MRI of neuroendocrine tumours

Neuroendocrine tumours (NETs) are often thought to be rare and rather recherché 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, incuding 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 12000 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. 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. Having taken into account all these considerations, most investigators would initiate investigation of a suspected or biochemically proven islet-cell tumour with cross-sectional imaging—either CT or MRI. This will clearly identify the larger lesions, allow assessment of the entire abdomen, and provide valuable information on the presence of hepatic metastates

CT/MRI in staging renal cell carcinoma

Renal cell carcinoma (RCC) is the eighth most common malignancy. It accounts for approximately 3% of newly diagnosed cancers and has been reported to occur in 11 out of 100000 individuals. The incidence of RCC has increased by 40% in the USA from 1974 to 1990. There appears to be a true increase in the incidence of RCC over and above that attributable to the increased number detected by abdominal cross-sectional imaging. This increase has been accompanied by improved 5-year survival as the tumors detected by imaging are diagnosed at an earlier stage when they are still resectable. The male to female ratio is approximately 2:1; the majority present in the fifth to seventh decade of life and the racial distribution is equal. The majority of cases occur sporadically, but predisposing factors can sometimes be identified. RCC occurs in about 36% of patients with von Hippel–Lindau disease and invasive RCC is three to six times more common among long-term dialysis patients than in the general population