Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Department of Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Clin J Gastroenterol. 2022 Dec;15(6):1078-1082. doi: 10.1007/s12328-022-01691-9. Epub 2022 Aug 31.
Neuroendocrine tumors are rare malignancies comprising neuroendocrine cells widely distributed in the human body. They occur in various organs of the body, most commonly in the gastrointestinal tract and pancreas in the Japanese population. Mixed neuroendocrine-non-neuroendocrine neoplasm is included in the 2019 WHO classification and defined as having more than 30% of both neuroendocrine and non-neuroendocrine tumor components. However, the number of reports on mixed neuroendocrine and non-neuroendocrine tumors is particularly small. Herein, we encountered a rare case of a tiny neuroendocrine carcinoma in a large flat-elevated rectal tumor resulting in rapid multiple liver metastases. This case was referred to our institution for endoscopic submucosal dissection. Histopathological analysis showed that tubular adenocarcinoma and adenoma were the predominant lesions. Moreover, the neuroendocrine carcinoma component was less than 3% of the total tumor, measuring approximately 5 mm. However, the neuroendocrine carcinoma component was found to be the most advanced part of the infiltrate (T1b at least; SM3.8 mm). Repeat computed tomography 1 week after endoscopic submucosal dissection for evaluating intraoperative perforation revealed liver metastasis, and chemotherapy is currently underway.
神经内分泌肿瘤是一种罕见的恶性肿瘤，由广泛分布于人体的神经内分泌细胞组成。它们发生在身体的各种器官中，在日本人群中最常见于胃肠道和胰腺。混合性神经内分泌-非神经内分泌肿瘤被纳入 2019 年 WHO 分类，并定义为具有超过 30%的神经内分泌和非神经内分泌肿瘤成分。然而，关于混合性神经内分泌和非神经内分泌肿瘤的报告数量特别少。在此，我们遇到了一个罕见的病例，一个大的扁平隆起直肠肿瘤中存在微小的神经内分泌癌，导致快速多发肝转移。该病例被转诊至我们机构进行内镜黏膜下剥离术。组织病理学分析显示管状腺癌和腺瘤是主要病变。此外，神经内分泌癌成分不到总肿瘤的 3%，大小约为 5 毫米。然而，神经内分泌癌成分是浸润最晚期的部分（至少 T1b；SM3.8 毫米）。内镜黏膜下剥离术 1 周后复查计算机断层扫描以评估术中穿孔，发现肝转移，目前正在进行化疗。
