672 for localization, the clip migration could be the main problem, and using fluoroscopy in the operating theater is troublesome and time consuming. However, in the case of hepatic flexure or splenic flexure colon cancer, by checking X-ray just after placing the endoscopic clip, we could precisely localize both flexure tumors easily. Intraoperative colonoscopy can be used for localization of the tumor, but it is also time consuming, and moreover, it can cause colonic insufflation that makes laparoscopic surgery difficult [14]. Properly placed tattoos are long lasting and can be placed at the time of diagnostic colonoscopy [15]. In the event of tattoo failure, one can use intraoperaitve colonoscopy for localization easily. In this study, we performed preoperative colonoscopic tattoo in three cases to localize the mid transverse colon cancer, colonoscopic clipping in three cases of hepatic flexure colon cancer, and barium enema in the other cases. There was no case with non-localization. We think that colonoscopic tattooing is effective in small mid transverse colon cancer, and endoscopic clipping is effective in small hepatic or splenic flexure colon cancer. Second is the laparoscopic identification, ligation, and lymph node dissection around the middle colic vessels. Fujita et al. reported laparoscopic techniques that can be used for identification of middle colic vessel. They suggested that the ventral aspect of the caudal portion of superior mesenteric vein be exposed, and the exposed vessel brought cephalad toward the caudal portion of the pancreas, with identification of the middle colic vessels [16]. Baca et al. introduced the ‘window technique’ for lymphadenectomy with simultaneous resection of the vascular stem [17]. Ichihara et al. introduced the technique of rotation of mesocolon to identify middle colic artery [18]. The authors have identified the middle colic vessels using surgical techniques introduced by Fujita in most of the cases, and the in case of slender patients we could directly identify pulsating middle colic artery by stretching the transverse mesocolon by traction of both ends of the transverse colon by the first assistant. Identifying middle colic vessels, excessive traction of the transverse mesocolon by the first assistant may cause tearing of the vein and bleeding. Moreover, the length of the gastrocolic trunk of Henle is relatively short, and attempt to control bleeding from the gastrocolic trunk of Henle can injure the superior mesenteric vein [19]. It is especially important for a laparoscopic colorectal surgeon to recognize the variable drainage of the right colic and middle colic vein to the gastrocolic trunk of Henle and to have a precise knowledge of superior right colic vein anatomy. Third is the low incidence of transverse colon cancer. Consecutive cases are needed for overcoming the learning curve. Therefore, it might take surgeons longer time to become experienced in the techniques used for laparoscopic transverse colon cancer resection. Int J Colorectal Dis (2008) 23:669–673 In this study, there were no significant differences between patients with TCC and OSCC in terms of operating time, blood loss, resection margin, and number of lymph nodes. Schlachta et al. reported that the operating time was longer in the TCC group compared to the OSCC group, and the number of harvested lymph nodes in the TCC group was greater than in the OSCC group because of the extended resection and larger specimens, as well as the need to attend to the middle colic vessels in patients with TCC [20]. However, in this study, there was no statistical difference in operating time and number of harvested lymph nodes, as well as the surgical outcomes between the two groups. We think that operating time could be similar in the TCC and OSCC groups in experienced hands, and actually, the extent of lymph node dissection in transverse colon cancer is not too wide than that of other site colon cancer, so there were no statistical differences in pathological outcomes between the two groups in this study. There was one case of colon injury proximal to anastomosis caused by electrocautery during the operation in the OSCC group; this was treated by a laparoscopic simple closure on postoperative day 3. Three cases of anastomosis leak, one case of right hemicolectomy, and two cases of anterior resection occurred in the OSCC group. A patient with anastomosis leak was diagnosed by clinical symptoms or sign, fecal or purulent discharge from drain, fever, leukocytosis, and peritoneal irritation sign. Radio- logic study using a water-soluble dye was not performed in this study. Of the three cases, one patient with a leak of anterior resection was treated conservatively successfully, and two patients with leak cases underwent laparoscopic re- operation. All other minor complications were successfully treated conservatively. Conversion to open surgery occurred in one case in the TCC group and in three cases in the OSCC group; these differences were not significant. Factors related to the tumor were the cause of conversion to open surgery. One case in the TCC group was converted to open surgery due to T4 lesion in the transverse colon cancer that invaded the anterior wall of the stomach. In the OSCC group, one case with a larger tumor that was hard to handle by laparoscopy, and two cases of sigmoid colon cancer that invaded the uterus were converted to open surgery. However, T4 colon cancer is not a contraindication for laparoscopy if en bloc resection could be performed with the laparoscopy. In those cases converted to open surgery, laparoscopic en bloc resection was impossible. This study has some weak points. First, the number of patients with transverse colon cancer is too small, making up 10% of the total colorectal cancer resection and 12% of the total laparoscopic colorectal resection in this study. The second is that although the data in this study were collected