A comparative analysis of the nervous system of cheilostome bryozoans

Background Bryozoans are sessile aquatic suspension feeders in mainly marine, but also freshwater habitats. Most species belong to the marine and calcified Cheilostomata. Since this taxon remains mostly unstudied regarding its neuroanatomy, the focus of this study is on the characterization and ground pattern reconstruction of the autozooidal nervous system based on six representatives. Results A common neuronal innervation pattern is present in the investigated species: a cerebral ganglion is located at the base of the lophophore, from where neurite bundles embrace the mouth opening to form a circumoral nerve ring. Four neurite bundles project from the cerebral ganglion to innervate peripheral areas, such as the body wall and parietal muscles via the tentacle sheath. Five neurite bundles comprise the main innervation of the visceral tract. Four neurite bundles innervate each tentacle via the circumoral nerve ring. Mediofrontal tentacle neurite bundles emerge directly from the nerve ring. Two laterofrontal- and one abfrontal tentacle neurite bundles emanate from radial neurite bundles, which originate from the cerebral ganglion and circumoral nerve ring in between two adjacent tentacles. The radial neurite bundles terminate in intertentacular pits and give rise to one abfrontal neurite bundle at the oral side and two abfrontal neurite bundles at the anal side. Similar patterns are described in ctenostome bryozoans. Conclusions The present results thus represent the gymnolaemate situation. Innervation of the tentacle sheath and visceral tract by fewer neurite bundles and tentacular innervation by four to six tentacle neurite bundles support cyclostomes as sister taxon to gymnolaemates. Phylactolaemates feature fewer distinct neurite bundles in visceral- and tentacle sheath innervation, which always split in nervous plexus, and their tentacles have six neurite bundles. Thus, this study supports phylactolaemates as sistergroup to myolaemates.

Ischemic proctitis 6 months after laparoscopic sigmoidectomy: a case report

Background Ischemic colitis is a common disease; however, its pathophysiology remains unclear, especially in ischemic proctitis after sigmoidectomy. We present a rare case of ischemic proctitis 6 months after laparoscopic sigmoidectomy. Case presentation The patient was a 60-year-old man with hypertension, type 2 diabetes, and hyperlipidemia. He was a smoker. He underwent laparoscopic sigmoidectomy for pathological stage I sigmoid colon cancer and was followed up without any adjuvant therapy. Six months after his surgery, he complained of lower abdominal discomfort, bloody stools, and tenesmus. Colonoscopy showed extensive rectal ulcers between the anastomotic site and the anal canal, which was particularly severe on the anal side several centimeters beyond the anastomosis. We provided non-surgical management, including hyperbaric oxygen therapy. The rectal ulcers had healed 48 days after the therapeutic intervention. He has not experienced any recurrence for 3.5 years. Conclusions While performing sigmoidectomy, it is important to consider the blood backflow from the anal side of the bowel carefully, especially for patients with risk factors of ischemic proctitis.

A Case of Laterally Spreading Tumor of the Rectum Treated by Endoscope-Assisted Transanal Tumor Resection

Background: Curability and function should be considered in resection of a rectal lateral spreading tumor (LST). Methods: We performed endoscopic transanal resection for a rectal LST extending to the pectinate line to preserve anal function and avoid a colostomy in 1 case and describe our procedure below. An 80-year-old man with a group 5 adenocarcinoma tub1/2 and no metastasis was considered for transanal resection because of his refusal of a colostomy and for staging and preservation of anal function. A strategy involving endoscopic submucosal dissection for mucosal cutting at the proximal side and for submucosal dissection of the maximum area at the anal side of the tumor was chosen, considering the tumor size. With the patient in a jackknife position, the tumor was marked circumferentially with coagulation dots, after which MucoUp with bosmin was injected into the submucosa at the proximal side. Mucosal and submucosal dissection was performed using DualKnife to remove the largest possible area toward the anal side. Transanal resection was performed under direct vision using an anal retractor, wherein the mucosa was cut circumferentially by extending the existing resection line along with removal of the submucosa. Results: En bloc resection with clear margins was achieved. Postoperatively, retroperitoneal emphysema was observed on a computed tomography scan, which resolved after 1 week of fasting. The patient was discharged 20 days postoperatively. Neither recurrence nor metastasis has been observed 1 year postoperatively. Conclusions: Our procedure enabled successful resection of a rectal LST with negative margins and preservation of anal function.

Rectal Cancer With Distally Spreading Intramural Metastasis: A Case Report and Review of the Literature

Introduction: Intramural metastasis (IM) is common in esophageal cancer, and it is an important factor in determining the resection area and tumor malignancy. However, IM is rare in rectal cancer; therefore, little is known about IM in rectal cancer, and the clinical significance remains unclear. Case Presentation: We describe a case of rectal cancer with distally spreading IM. A 58-year-old man consulted a primary care physician, with a chief complaint of constipation; tests revealed a high carcinoembryonic antigen value. A colonoscopy revealed a type 2, advanced rectal tumor, which covered two-thirds of the circumference of the upper rectum. In addition, 3 protruding lesions were observed under the normal mucosa on the anal side of the primary tumor. A laparoscopic low anterior resection was performed. Pathologic findings showed that the primary tumor was a moderate-to-well-differentiated adenocarcinoma with a cribriform structure. The 3 lesions on the anal side found under normal mucosa were separate from the primary tumor, but morphologically similar to the primary adenocarcinoma; therefore, these were diagnosed as IMs. Based on a review of previous case reports, rectal carcinomas were often accompanied by vascular invasions and lymph-node metastases. Moreover, in rectal cancer, tumors with IMs often show vascular invasion. Therefore, we assumed that IM could be a marker of poor prognosis. Conclusion: This study revealed that, in surgery, detection of a distally spreading IM is an important finding for determining the optimal surgical resection margin.

PS01.080: A CASE REPORT OF JEJUNAL VARICEAL BLEEDING SUCCESSFULLY TREATED WITH PERCUTANEOUS TRANSHEPATIC OBLITERATION AFTER SURGERY OF ESOPHAGOGASTRIC JUNCTIONAL CARCINOMA

Background Varicose veins in the esophagogastric junction rarely occur after surgery of esophagogastric junctional carcinoma, because the collateral pathway of the left gastric vein and short gastric vein was sacrificed. We presented a case of jejunal variceal bleeding successfully treated with percutaneous transhepatic obliteration after surgery of esophagogastric junctional carcinoma. Methods Case report. Results A 50-year-old man with alcoholic liver cirrhosis (Child-B) was admitted for abdominal pain, three months after proximal gastrectomy for esophagogastric junctional carcinoma. After diagnosed with peritonitis due to jejunal perforation, emergency surgery was performed. The next day after surgery, he had developed a lot of black stool. Gastroduodenoscopy revealed the variceal bleeding at the anal side of the esophagojejunal anastomois. Although endoscopic clipping was performed, intermittent bleeding was observed for several days. Since the contrast-enhanced computed tomography scanning revealed jejunal vein dilation at the anal side of the esophagojejunal anastomois, we planned to perform percutaneous transhepatic obliteration. Percutaneous transhepatic portography revealed jejunal varices and drained to the inferior vena cava, and continuously obliterated by 5% EOI (Ethanolamine oleate iopamidol). He was discharged without re-bleeding on the 14th day after the obliteration. Conclusion Percutaneous transhepatic obliteration might be a useful treatment option for jejunal variceal bleeding after surgery of esophagogastric junctional carcinoma. Disclosure All authors have declared no conflicts of interest.

Successful Laparoscopic Treatment for Refractory Rectovaginal Fistula of Behçet's Disease: A Case Report and Review of the Literature

Abstract Introduction: Rectovaginal fistula caused by Behçet's disease is extremely rare, and the clinical course is very unfavorable. We describe rectovaginal fistula of Behçet's disease with successful laparoscopic treatment, and review the literature. Case presentation: A 30-year-old woman with Behçet's disease was diagnosed with rectovaginal fistula, and treated medically after fecal diversion colostomy. However, the fistula remained, and she underwent radical surgery. Laparoscopically, after mobilization of the rectum, the fistula was removed. The rectum was transected on the anal side of the fistula, and removed after extraction through the vaginal incision. The vaginal incision was repaired by suturing, and rectal anastomosis was performed using a double-stapling technique. The omentum was fixed between the rectum and vagina, and the operation was completed. Six months after the laparoscopic surgery, no evidence of fistula recurrence has been seen on colonoscopy. Conclusion: We have reported a rare case of rectovaginal fistula of Behçet's disease treated with an altogether new surgical approach that might prove effective for refractory rectovaginal fistula.

A New Laparoscopic Surgical Procedure to Achieve Sufficient Mesorectal Excision in Upper Rectal Cancer

Objective. Mesorectal excision corresponding to the location of a tumor, termed tumor-specific mesorectal excision (TSME), is commonly performed for resection of upper rectal cancer. We devised a new laparoscopic procedure for sufficient TSME with rectal transection followed by mesorectal excision.Operative Technique. After mobilization of the sigmoid colon and ligation of inferior mesenteric vessels, we dissected the mesorectum along the layer of the planned total mesorectal excision. The rectal wall was carefully separated from the mesorectum at the appropriate anal side from the tumor. After the rectum was isolated and transected using an endoscopic linear stapler, the rectal stump drew immediately toward the anal side, enabling the mesorectum to be identified clearly. In this way, sufficient TSME can be performed easily and accurately. This technique has been successfully conducted on 19 patients.Conclusion. This laparoscopic technique is a feasible and reliable procedure for achieving sufficient TSME.