─特殊な組織型を呈する早期胃癌─カルチノイド・内分泌細胞癌

Gastric Carcinoid and Endocrine Cell Carcinoma

要旨●胃カルチノイド（NET）と内分泌細胞癌（NEC）はいずれも腫瘍性内分泌細胞から構成される腫瘍であるが，発生起源や臨床像が全く異なる．前者は胃内のenterochromaffin様細胞（ECL細胞）由来で多彩な背景因子を有し，肉眼的には小型の粘膜下腫瘍を形成し，予後は良好である．後者は腺癌の脱分化が由来で，主に2型の形態を示し，予後が著明に不良である．WHO分類では同系統の腫瘍のように分類されているが，全く異質の腫瘍であるとの理解が臨床的取り扱いにも有用である．

　Both gastric carcinoid（neuroendocrine tumor）and endocrine cell carcinoma（neuroendocrine carcinoma）are tumors that comprise neoplastic endocrine cells. The origins and clinical behaviors of these tumors are entirely different. Neuroendocrine tumor is derived from the enterochromaffin-like cells in the stomach. It is characterized by various background factors such as macroscopical form of a small submucosal tumor, and good prognosis. On the contrary, endocrine cell carcinoma is derived from adenocarcinoma dedifferentiation and mainly exhibits a type 2 form with a markedly poor prognosis. The World Health Organization classifies these tumors in to the same strain. However, the understanding that these tumors are completely different neoplasms is also useful for their clinical management.