Carcinoid tumours. Frequency in a defined population during a 12-year period.

The frequency of carcinoids was studied in a 12-year-period (1958-1969) in Malmo, a town with a population of 220,000 at the beginning of the period and 250,000 at the end of it. Of all persons who had died in Malmo, 46 per cent were necropsied in the first year of the study and 70 per cent in the last (altogether 62.6 per cent). The series was examined in a uniform way at one department of pathology. Carcinoid tumours were found in 1.22 per cent (199 patients) of patients comprised in the entire necropsy series (16,294 autopsies). Bronchial carcinoid accounted for 0.1 percent, the remaining lesions were found in the digestive tract. About 90 per cent of the carcinoids were found incidentally at necropsy. During the same period, 44 carcinoids were diagnosed in surgical specimens examined in Malmo. The average annual frequency of carcinoid in the entire series was about 8.4 per 100,000 inhabitants, which is about 7 times as high as that recorded in the National Cancer Register applying to the whole of Sweden. The value of such country-wide reports is discussed. The carcinoid syndrome is extremely rare and was observed only once during the entire 12-year-period. The localization, frequency of metastases and sex-distribution of carcinoids are described and discussed in detail.