[The life of S. Oberndorfer: the proposer of the term "carcinoid"--the outcome of a seed in the past 100 years].

Since Siegfried Oberndorfer proposed the term "carcinoid" in 1907, over 100 years have passed. In 1876, he was born at Munich and, in 1907 reported a series of 6 cases of "carcinoids" in the small intestine as benign tumorlets. In 1929, he partly revised his initial concept of carcinoid, pointing out some cases being malignant with metastases. In 1944, he demised with a thymoma. A proposal of the concept of GEP system in 1973 was followed by proposals of the concept of neuroendocrine tumor (NET) and the GEP-NET classification based on the WHO histological classification, later developing into the TNM classification by the ENETS (European NET Society), which was founded in 2004. Carcinoids are now included in a corner of the GEP-NET classification with a somewhat confusing expression of "benign biological(clinical) behavior" vs. histological malignancy.