Neuroendokrine Neoplasien des Magens

INTRODUCTION: Neuroendocrine Neoplasms are classified according to the new WHO classification in (1.) well differentiated neuroendocrine tumors G1 (NET G1, Ki67 \textless/= 2 or mitosis count \textless2) and (2.) well differentiated neuroendocrine tumors G2 (NET G2, Ki67 3-20 or mitosis count 2-20) and (3.) poorly differentiated neuroendocrine carcinomas G3 (NEC G3, Ki67 \textgreater 20 or mitosis count \textgreater20). MATERIAL AND METHODS: In this study 310 NENs of the Ludwig-Maximilians-University in Munich were reevaluated according to the new WHO classification. RESULTS: 7% of the analyzed NENs were presented as neoplasias of the stomach. In NENs of the stomach three distinct subtypes are recognized: (1) type 1 associated with autoimmune chronic atrophic gastritis (2) type 2, associated with multiple endocrine neoplasia (MEN1) and Zollinger-Ellison Syndrom; and (3) type 3, sporadic tumors. DISCUSSION: Precursor lesions (i. e. hyperplasia of the ECL cells) are found in patients with hypergastrinaemia (type 1 and 2). This article should provide insights into the diagnosis of NENs of the stomach with emphasis on the new international standard.