Carcinoids (carcinoid tumors) are rare tumors that derive from hormone-producing (endocrine) cells and therefore often produce hormones. Carcinoid tumors generally grow slowly and mainly develop in the rectum, the lungs, small intestines, appendix, stomach or thymus gland. Both (neuro) endocrine tumors of the pancreas and carcinoid tumors are called neuroendocrine neoplasms (neoplasias). The term islet cell tumor of the pancreas is also used and is synonymous with the term (neuro) endocrine tumor (neoplasia) of the pancreas. The prefix "neuro" in the word neuroendocrine tumor reveals the similarity these endocrine tumor cells share with nerve cells. Despite their infrequent occurrence, the (neuro) endocrine tumors (neoplasias) have had an astounding multitude of names and synonyms.

The German pathologist Siegfried Oberndorfer coined the term carcinoid in 1907 to indicate the usually favorable course and most often good prognosis of this type of cancer. Oberndorfer allocated carcinoid tumors to a category between clearly malignant tumors and clearly benign tumors.

Despite the fact that the term carcinoid is considered by some to be a misnomer, most patients and doctors throughout the world use this term today, particularly in Japan, China, Korea, India, Australia, North America, Brazil and Russia. To avoid turning communication and knowledge of this disease into a discussion on terms and nomenclature, both neuroendocrine tumor and neuroendocrine neoplasia as well as the term carcinoid will be used throughout this website. According to the current  WHO classification (of 2010) G1-well differentiated neuroendocrine tumors are called carcinoids.

Figure 1:

Siegfried Oberndorfer (1876-1944, died in Istanbul)

figure 1

Modified according to Modlin et al., Arch Surg 2007; 142:187-197 and Lancet Oncology 2008; 9:61-72

Gastric and intestinal carcinoids, as well as islet cell tumors of the pancreas, often produce hormones and transmitter substances that regulate various bodily functions. These substances are often released in great amounts into the blood stream by hormone-active neuroendocrine tumors and cause specific ailments (symptoms) in the body. Often persistent diarrhea, abdominal cramps/pain, heartburn, gastric and duodenal ulcers, or flush attacks are the result. Interestingly, carcinoids of the appendix or rectum produce no such symptoms in 99% of the cases.

Hormone-producing cells, i.e. (neuro) endocrine cells are found throughout the entire body. Therefore, (neuro) endocrine tumors could, in principle, also occur anywhere in the body. Sometimes neuroendocrine differentiated tumor cells are only a component of a mixed endocrine-exocrine tumor. Since the purely neuroendocrine tumor type is the most prevalent, the following forum will be limited to neuroendocrine tumors in the traditional meaning. For information on so-called mixed tumors (endocrine-exocrine or amphicrine tumors) please see other sources or scientific literature as they will not be discussed here.

Prof. Dr. med. Hans Scherübl


Center of Neuroendocrine Tumors
Prof. Dr. med. Hans Scherübl
Vivantes Klinikum Am Urban
Academic Teaching Hospital of Charité-University Medicine, Berlin
Dieffenbachstraße 1
10967 Berlin, Germany
Tel: + 49 30 130 225201
Fax: + 49 30 130 225205
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.