Neuroendocrine tumours in various organ systems in a ten-year period.

Neuroendocrine cells are present in various organ systems. These widely distributed cells as well as their histogenetically related tumours can produce various peptides and peptide hormones. From 1984 to 1993, 349 neuroendocrine tumours were found among 511,382 histological diagnoses at the Institute of Pathology of the Medical School of the Karl Franzens University in Graz. In 30% carcinoid of the appendix was diagnosed, in 16% carcinoid of the colorectum, in 9% carcinoid of the small intestine and in 2% duodenal carcinoid. Carcinoid of the stomach was detected in 14%. Seven of these cases showed microcarcinoidosis and five of them were combined with an adenocarcinoma. Carcinoid of the oesophagus was present in 1%, neuroendocrine pancreatic tumours in 6%. Neuroendocrine tumours of the bronchial system were found in 12%, medullary thyroid cancer in 5%. In 1% a Merkel-cell tumour was diagnosed. Other more rare localizations of neuroendocrine tumours were the uterus, ovary, breast, testes, epididymis, anal region and the upper respiratory tract.