Carcinoma located in a right-sided sigmoid colon: A case report

lNTRODUCTlON

Recognizing variations in the sigmoid colon is of key importance to surgeons and radiologists. Here, we report an atypical anatomic variation of a right-sided sigmoid colon with carcinoma, which was incidentally observed during an emergency computed tomography (CT) scan for abdominal pain. To the best of our knowledge, this is the first clinical case of a carcinoma located in a right-sided sigmoid colon detected by a preoperative CT scan. We present the following case in accordance with the CARE Reporting Checklist.

CASE PRESENTATlON

Chief complaints

A 56-year-old Chinese man was admitted to our hospital with abdominal pain in the right lower quadrant for 3 days.

History of present illness

The surgeons found a mass that almost completely blocked the lumen of the sigmoid colon. The redundant sigmoid colon was located on the right side of the ascending colon and cecum and was supplied by the branches of the inferior mesenteric artery, which ran to the right instead of its standard left-sided course. The descending colon started at the splenic flexure and crossed to the right at the level of the L4 vertebra, and occupied the subhepatic region to continue as the sigmoid colon. The small intestine was normal. Pathological examination revealed an infiltrative mucinous adenocarcinoma with two lymph node metastases, pT4N1M0 stage IIIB (UICC-TNM: 8edition).

History of past illness

The patient had no previous surgical history.

3. 另行解释执行依据。即由执行机关商请作出生效法律文书的审判组织或其他机构作出进一步解释。该种做法主要是：执行机关对于执行依据不明确的执行案件，不能直接采取相关驳回申请或终结执行的方式结案，而是应当有所作为，即可以通过一定的解释方法来界定执行依据中所列明的内容。对于解释方法，应该紧紧围绕执行依据本身进行，首先运用文义解释的方法，相对客观地来解读执行依据所列举的执行内容；如果通过文义解释可以解释出多个结论，则为了合理平衡当事人之间的权益，适宜结合个案的具体情况，明确执行依据的相关内容[2]。

Personal and family history

The patient did not have a history of smoking or drinking. There was no personal or family history of acute or chronic diseases.

Physical examination upon admission

The patient was 169 cm tall and weighed 65 kg. Physical examination revealed tenderness in the right lower quadrant, but no palpable mass was found.

Laboratory examinations

Laboratory tests showed moderate increases in platelets and CA724, and normal levels of white blood cells and CA199. No abnormal results were found in other biochemical tests.

Imaging examinations

We report a rare anomaly of the right-sided sigmoid colon with carcinoma that could be detected by careful examination with a preoperative CT scan. This is a major congenital colon anomaly that should be recognized preoperatively and needs to be differentiated from the ascending colon and pericecal hernia to prevent errors and other surgical complications.

Colonoscopy showed an annular stricture of the sigmoid colon caused by a tumor 28 cm from the anus. Subsequent biopsy indicated malignancy.

FlNAL DlAGNOSlS

Due to inconclusive radiological signs, the patient underwent laparoscopic exploration. Intraoperatively, the surgeons detected atypical positions of both the sigmoid colon and descending colon. They converted the surgery to an open operation for safety considerations.

The patient had experienced irregular and formless bowel movements for three months prior to presentation at our hospital. The patient also had right lower quadrant abdominal pain, which could not be relieved after defecation. The patient had no other accompanying symptoms, including any obvious symptoms of bowel obstruction.

（三）促进文明城市建设。一个城市的阅读数量和质量，是一个城市文明形成的显性和潜在的双向元素。“书中自有黄金屋，书中自有千钟粟……”而一个文明的、高素质的人文环境构架下的城市，文明、和谐皆为水到渠成之事。

三峡旅游作为大旅游空间，仅靠少数经典景区的“只言片语”是不够说服游客的，况且三峡部分景区已明显处于衰退期，亟需挖掘资源存量，三峡旅游需要核心扩散，即对三峡核心元素进行提炼，这个核心元素不能是局部的、片面的，形成覆盖全域的中心节点是未来三峡的旅游发展之道。

TREATMENT

Lyu LJ and Yao WW wrote the manuscript; all authors have read and approve the final manuscript.

OUTCOME AND FOLLOW-UP

创新是事物发展的源泉，改革是事物发展的不竭动力，新时代我国群众体育领域研究应当以健康中国战略为引领，关注城乡群众体育协调发展，以全民健身战略为引领，关注群体与竞体的协调发展，以体育强国战略为引领，关注我国群众体育文化发展，从而最终实现我国群众体育的全面、可持续发展。

DlSCUSSlON

The sigmoid colon shows the greatest variation in length and position[1]. The variation in length is mainly related to racial differences and a high-fiber diet[2], the position of the sigmoid colon loop is a means of adapting to the general length of the sigmoid colon[2]. A study by Saxena[3] suggested that the sigmoid colon of young children (age ＜ 5 years) is often situated entirely on the right side for redundancy; this is not the case in adults. The presence of a right-sided sigmoid colon is very rare in adults and may be related to fixation anomalies[1], redundancy of the colon, or secondary rotation of the colon during embryogenesis[4].

In most cases of right-side colon carcinoma, the carcinoma is observed to be located in the ascending colon. In our case, circumferential wall thickening of the colon occupied the subhepatic region on the right of the ascending colon, and the ileocecal junction was displaced toward the left at the level of the L4 transverse process instead of the right pelvic region, indicating that the cecum was undescended due to midgut malrotation during embryogenesis[4]. Colonoscopy revealed a stricture 28 cm from the anus,demonstrating a sigmoid colon other than the ascending colon. The identification of the tumor location is crucial for determining the appropriate clinical course because the sigmoid colon and ascending colon have different embryological origins[5], and a recent study[6] demonstrated that right-sided colon carcinomas exhibit exophytic pathological behavior and poorer overall survival than left-sided colon carcinomas.

按季节分析IMERG估计降水的空报率FAR,结果表明:中国大陆的FAR在夏季最低,约为0.52;其次是秋季和春季,分别为0.65和0.64;冬季最高,约为0.75。中国大陆东、西部的FAR的季节变化趋势与整个中国大陆完全相同,各季都是西部地区高、东部地区低。西部夏季FAR最低时也超过了0.6,冬季最高时约为0.9。除秋季相差约0.1之外,其他季节东、西部地区的FAR相差约0.2(图5b)。

Shrivastava[8] first described the right-sided sigmoid colon in a cadaveric study in 2013. Flores-R íos[9] reported a case of secondary right-sided descending and sigmoid colon caused by a wandering spleen due to laxity or abnormal development of the peritoneal ligaments, which was different from our case. Subsequently, there were two case reports[1,10] of right-sided sigmoid colons,which were discovered incidentally during surgery.

To the best of our knowledge, this is the first clinical case of carcinoma located in the right-sided sigmoid colon revealed by a preoperative CT scan and confirmed by surgery. Surgeons and radiologists should be aware of this rare variation when examining patients experiencing abdominal pain in the right lower quadrant.

The limitation of our case was the lack of appropriate intraoperative images compatible with the volume rendering image (Figure 2C), which could have provided readers with an intuitive understanding.

利用商业保险分担农业风险，发挥市场对灾后可持续经营的补偿作用；对于安全要求和生产水平高的农业经济作物，应让市场多多参与，加快经济作物的农业保险商业化进程；减少政府干预，分清公共资源与私人物品的界限，提高政府工作效率，发挥市场在资源配置中的基础作用［3］。

选取云南省第三人民医院2017年1月—2017年6月收治的肥胖2型糖尿病患者95例，按治疗方法分为对照组47例、观察组48例。两组一般资料比较无显著差异，见表1。本研究已通过本院伦理委员会审核和批准。

In the present case, the colon with wall thickening on the right side of the ascending colon was similar to a rare type of internal hernia occurring near the cecum, namely, pericecal hernia[7]. However,pericecal hernia usually involves a small bowel other than the sigmoid colon; such pericecal hernias usually produce acute intestinal obstruction, which can be confirmed by CT. In addition, it is expected that the descending colon and sigmoid colon should be observed in the standard position relative to the pericecal hernia and the inferior mesenteric artery. On CT images of the present case, no small bowel herniation or obvious dilation was observed. The descending colon crossed to the right side at the level of the L4 vertebra, where it entered the peritoneal cavity and continued as the sigmoid colon on the right side. Notably, the inferior mesenteric artery ran to the right instead of its normal left-sided course.

CONCLUSlON

CT showed an atypical location of the redundant sigmoid colon with heterogeneously enhanced circumferential wall thickening on the right side of the cecum and ascending colon (Figures 1 and 2). We reported the atypical location of the sigmoid colon with a mass, suspected the presence of a pericecal hernia, and informed the surgeons accordingly.

FOOTNOTES

The surgeons performed a hemicolectomy with regional lymphadenectomy during laparotomy. No bowel perforation was observed.

Written informed consent was obtained from the patient for publication of this report.

The patient was discharged on postoperative day 7 without any complications. Moreover, there were no signs of recurrence or metastasis during the 3-month follow-up period.

The authors declare that they have no conflicts of interest.

The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).

新课程改革下的高中物理教学不再是教师一个人完成的教学活动，在课堂中更多是突出了学生的主体地位.在物理实验课程中，学生是实验的实际操作主体，在实验过程中，学生能都独立思考实验步骤和实验过程，从而得出实验结果，可以通过反复的实验验证自己的猜测，培养自身独立思考物理的能力.学生在自身实际操作过程中还可以发现问题，对于自己操作过程中的不足之处能够及时的发现和弥补，不仅能够有效地掌握相关的知识，更能够不断的提升自身的实际操作能力.

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China

Liang-Jing Lyu 0000-0003-4643-9740; Wei-Wu Yao 0002-1536-9324.

Ma YJ

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自由自在、梦想理想、独立自主、健康美貌、事业成功、喜欢就好、想爱就爱、世界和平、保护地球等，都被她们罗列了一遍，兴奋无比。那一刻蒲琳觉得，原来有张盈盈陪伴着自己的这些年里，自己什么都没有缺过。

Ma YJ