Department of Surgery, Dokkyo Medical University Saitama Medical Center, Koshigaya, Japan.
Department of Gastric Surgery, National Cancer Center Hospital, 5-1-1 Tsukiji, Cyuo-ku, Tokyo, 104-0045, Japan.
World J Surg Oncol. 2019 Mar 19;17(1):53. doi: 10.1186/s12957-019-1594-8.
Primary gastric squamous cell carcinoma (SCC) is a very rare disease. The origin of this tumor remains unclear, although there are some hypotheses. A 60-year-old man consulted a previous physician complaining of upper abdominal pain. Esophagogastroduodenoscopy revealed type 2 gastric cancer, and the patient was referred to our hospital. After close examination, the patient was diagnosed as cStage IIA gastric adenocarcinoma, and distal gastrectomy was performed. Histochemical studies showed typical findings of SCC, and the tumor was surrounded by intestinal metaplasia. Immunohistochemical examination was positive for cytokeratin (CK) 5/6 and caudal-type homeobox protein 2 (CDX2) and negative for p63/p40.
The results of immunostaining for CK5/6 supported that this tumor was SCC, but the question why p63/p40 were negative and CDX2 was positive still remained. Concerning about the origin of p63/p40 and CDX2, it was suggested that the tumor cells were not derived from ectopic squamous epithelium but from intestinal metaplasia. And tumor cells looked like homogeneous and squamous metaplasia was not observed. These findings supported the idea that these tumor cells arose from stem cells in the intestinal metaplasia of the stomach.
原发性胃鳞状细胞癌（SCC）是一种非常罕见的疾病。尽管有一些假说，但这种肿瘤的起源仍不清楚。一位 60 岁的男性因上腹痛就诊于一位先前的医生。食管胃十二指肠镜检查显示 2 型胃癌，患者被转至我院。经过仔细检查，患者被诊断为 cStage IIA 胃腺癌，并进行了远端胃切除术。组织化学研究显示出典型的 SCC 发现，肿瘤周围有肠上皮化生。免疫组织化学检查 CK5/6 和尾型同源盒蛋白 2（CDX2）阳性，p63/p40 阴性。
CK5/6 的免疫染色结果支持该肿瘤为 SCC，但 p63/p40 阴性而 CDX2 阳性的原因仍不清楚。关于 p63/p40 和 CDX2 的起源，提示肿瘤细胞不是来自异位鳞状上皮，而是来自肠上皮化生。而且肿瘤细胞看起来均匀，没有观察到鳞状化生。这些发现支持这些肿瘤细胞来源于胃肠上皮化生的干细胞的观点。
