Gastrointestinal Neuroendocrine Tumors

Gastrointestinal carcinoid tumors date back to 1888 when Otto Lubarsch found multiple tumors in the distal ileum of two patients at autopsy (Lubarsch, 1888). The German pathologist Siegfried Oberndorfer was the first who used the term “Karzinoide Tumoren”, the English translation of which is “carcinoid tumor”. He coined this term because these tumors behaved less aggressively than true carcinomas (Oberndorfer, 1907). Oberndorfer contributed to the Department of Pathology of Istanbul University where he remained full professor and director until his death in 1944 (Dogan & Hot, 2010; Klöppel et al., 2007). In 1914, Gosset and Masson first mentioned neuroendocrine features of carcinoid tumors. In 1954, Thorson and co-workers described the term "carcinoid syndrome" after they found that the tumors contained serotonin and patients with small intestinal carcinoid tumor and liver metastases presented with the characteristic symptoms of diarrhea, flushing, asthma, and right heart failure (Thorson et al., 1954). It was soon recognized as a distinct entity after they were reported in several organs belonging to bronchopulmonary system and gastrointestinal tract (Yalcin, 2006). Although better named as “neuroendocrine tumors” after the WHO meeting in 2000, these tumors have been traditionally called “carcinoids” especially at some specific locations such as the gastrointestinal tract. Therefore, the terms “carcinoid tumor” and “neuroendocrine tumor” are used interchangeably throughout the text.