Shu Kuramoto

Flat early cancers of the large intestine

From January 1976 to December 1987, 37 early colorectal cancers of the flat type were treated. Thirty‐four of them (91.9%) were not accompanied by adenoma, and were thought to have arisen de novo. There is indeed a de novo route of cancer development in the human large intestine, and cancers de novo merely show polypoid growth. Flat type cancers arising de novo tend to reach deeper layers at an earlier stage than polypoid‐type carcinomas in adenoma. Of those with a diameter of less than 10 mm, only 40% stayed in the mucosa. Consequently, advanced cancers cannot be prevented by snare polypectomy alone. More attention should be directed to the discovery of small, flat, nonpolypoid cancers.

Minute cancers arising de novo in the human large intestine

In order to search for the histogenesis and progression of colorectal cancer, the background mucosas of 18 patients with a single colorectal cancer, apart from familial adenomatosis coli, were studied by a step sectioning method. Three early minute cancers (3‐5 mm in diameter) were detected in the apparently normal mucosa, and two cancers in the adenoma (focal cancer in adenomatous polyp). The three early cancers had no evidence of preexisting adenoma, so they were considered to be de novo cancers. In form they were depressed, flat, and slightly elevated. In humans, de novo cancer has an important significance in histogenesis and treatment of colorectal cancer. Clinically, it is also important to recognize the early phase of colorectal cancer in flat type as well as polypoid type.

Depressed adenoma in the large intestine

To clarify the presence of depressed adenomas in the human large intestine, a prospective study was performed from January 1986 to December 1987. During these two years, 997 colonoscopies were conducted in patients, bdexcluding cases of familial adenomatosis coli. Of 32 small, depressed lesions biopsied, seven were depressed adenomas, demonstrating that depressed adenomas do exist in the colon and rectum, and can be detected endoscopically. Resembling a sucker, they are easily detected through inflation and deflation.

Lymphangioma of the large intestine

Lymphangiomas of the large intestine have been reported more frequently since the development and widespread use of the colonic fiberscope. It is possible to endoscopically diangnose lymphangiomas because they are lustrous and smooth on the surface, pliable on compression, and half of them have a stalk or a waist at the base. Lymphangiomas of the colon and rectum under 20 mm in diameter can be safely resected by electrocautery, thereby avoiding unnecessary operation.

Peutz-Jeghers syndrome manifesting complete intussusception of the appendix and associated with a focal cancer of the duodenum and a cystadenocarcinoma of the pancreas : Report of a case

The unusual occurrence of an “inside-out” appendix reported here is a case of complete intussusception of the appendix of a 45-year-old woman with Peutz-Jeghers syndrome in whom the diagnosis of intussusception was made preoperatively. At laparotomy, the lead point of intussusceptum was revealed to be a Peutz-Jeghers syndrome polyp of the appendix. There was also a cystic lesion in the pancreas, and subsequent distal pancreatectomy revealed a cystadenocarcinoma of the pancreas. Two jejunal Peutz-Jeghers syndrome polyps and two duodenal Peutz-Jeghers syndrome polyps were foundvia intraoperative endoscopies. The duodenal polyps were endoscopically removed, whereas a jejunal wedge resection was performed for the adjoining jejunal polyps. One of the two duodenal polyps possessed an adenocarcinoma focus. To our knowledge, this is the first report of complete intussusception of the appendix caused by a Peutz-Jeghers syndrome polyp.

A rare case of pseudomyxoma peritonei presenting an unusual inguinal hernia and splenic metastasis

Abstract Pseudomyxoma peritonei (PMP) is a rare clinical entity in which a diffuse collection of intraperitoneal gelatinous fluid is associated with gelatinous implants on the peritoneal surfaces and omentum. Hematogenic or lymphatic metastasis is extremely rare. In addition, an inguinal mass as an initial presentation is also relatively rare. This is a case report of a PMP patient who had splenic metastasis and showed an inguinal tumor as an initial presentation. A 59‐year‐old female patient, who had undergone bilateral oophorectomy because of a ruptured ovarian mucinous tumor of boderline malignancy 12 years previously, presented a presumptive diagnosis of a left inguinal irreducible hernia. Computed tomography revealed a low density mass in the pelvic cavity and in the inguinal lesion, as well as in the spleen without any diseases around the organ. The preoperative serum carcinoembryonic antigen (CEA) level was elevated. The patient underwent a resection of gelatinous tumor in the pelvic cavity, splenectomy, and appendectomy, as well as left inguinal herniorrhaphy. Histological examinations revealed a splenic metastasis of PMP originating from the ovarian low‐grade mucinous tumor. She received postoperative intraperitoneal lavage as well as chemotherapy, and has survived for over 7 years postoperatively without any evidence of recurrence, as confirmed by repeated follow‐up CT examinations and CEA determination. Splenic metastasis of PMP is extremely rare; this represents only the third reported case of its kind in the literature. Furthermore, it should be noted that an inguinal tumor can sometimes be an initial presentation of PMP.

Leiomyosarcoma Originating in Meckel's Diverticulum: Report of a Case and a Review of 59 Cases in the English Literature

A 49-year-old woman was referred to our hospital with complaints of epigastric colicky pain and high fever. Abdominal computed tomography and ultrasonography showed a solid tumor in the lower abdomen. Laparotomy revealed a neoplastic mass arising in Meckels diverticulum; therefore, a segment of the ileum, including the tumor-possessing diverticulum, was resected with a lymph node dissection. A histologic examination confirmed the lesion to be leiomyosarcoma. In the English literature, 59 cases of leiomyosarcoma in Meckels diverticulum were reported from 1941 to 1994. The majority of patients were in their 4th decade of life, with both sexes equally affected. The most frequent symptoms associated with this disease were abdominal pain with nausea, vomiting, and melena. The majority were larger than egg-size. Although Meckels diverticulum is difficult to diagnose preoperatively, mesenteric arteriography may at times prove useful. The standard management of this particular tumor is wide segmental resection, including the tumor and diverticulum with lymph node dissection.

Denervation promotes the development of cancer-related lesions in the gastric remnant.

Innervation of the gastric mucosa plays an important role in its defense mechanism. In a previous study, gastrectomy with denervation promoted tumorigenesis in the gastric body in rats after administration of a carcinogenic agent. In this study we investigated the induced gastric mucosal changes from the viewpoint of mucin histochemistry. Gastrectomy with denervation promoted the development of intestinal metaplasia, dysplasia, and carcinoma in the gastric body. Proliferating cell nuclear antigen labeling indexes as a marker for cell kinetics were significantly elevated in the denervated group. Analysis of mucin histochemistry by staining with paradoxical concanavalin A (PCA) and galactose oxidase-Schiff (GOS), which are markers for expression of the gastric phenotype, revealed that these mucins were positive in submucosal adenocystic proliferation and carcinoma at the anastomotic site. Conversely, in the gastric body these mucins disappeared with progression of dysplasia, and carcinoma cells contained neither PCA- nor GOS-positive mucins. These results suggest that there are two different processes of carcinogenesis in the gastric remnant, depending on the location, and that denervation of the remnant gastric mucosa promotes the development of cancer-related lesions in the gastric body.

Familial adenomatous polyposis: a case report and histologic mucin study.

Adenocarcinoma arising at an ileostomy is uncommon, and only 29 cases have been reported in the literature. The case of a 54-year-old man who developed an adenocarcinoma at a Brooke ileostomy is reported. The ileostomy had been fashioned 21 years earlier after proctocolectomy for familial adenomatous polyposis (FAP). A wide local excision of the stoma was performed, and a new Brooke ileostomy was fashioned on the opposite side of the abdomen. Histopathologic examination revealed a well-differentiated adenocarcinoma with early invasion of the submucosa. On hematoxylin and eosin staining, the ileal mucosa adjacent to the tumor showed signs of colonic metaplasia, including loss of villous architecture and a reduced number of Paneth cells. Mucin staining using the high iron diamine-alcian blue stain demonstrated a mixture of sulfomucin and sialomucin in the ileal mucosa near the tumor, confirming colonic metaplasia. Ileostomy site carcinogenesis can be attributed to both the colonic metaplasia and the inherent nature of FAP or ulcerative colitis (UC), where colonic mucosa is susceptible to adenoma formation or dysplasia. Longstanding ileostomies in patients with FAP or UC should be followed to exclude the development of adenoma, dysplasia, or cancer.

Flat cancers do develop in the polyp-free large intestine.

PURPOSE AND BACKGROUND: Qualitative and quantitative analysis of many flat early cancers that have been discovered during the last decade led us to recognize that a flat route of cancer developmentde novois as important a route as the polypoid one. We aim to prove through a longitudinal study that these flat early cancers indeed develop in flat mucosa and not in an adenomatous polyp. METHODS: From January 1, 1990, to July 31, 1994, 554 patients underwent at least two colonoscopies. These patients consisted of 364 males, and average age was 59 years. We searched for flat early cancers developing in polyp-free colorectal mucosa on or after a second colonoscopy. Polyp-free mucosa here means an intestinal segment proved to possess no adenomatous polyp during the preceding colonoscopies, irrespective of the presence of polyps else-where. RESULTS: Four flat early cancers were found developing in polyp-free colonic mucosa in four patients. Average age of the patients was 67 years. Locations of the cancers were the transverse (3) and descending colons (1). The shapes were all depressed, and average size of the lesions was 11 mm. Two lesions were endoscopically resected, and two by surgery. CONCLUSION: These four depressed cancers developing in polyp-free mucosa show that flat early colorectal cancers do arisede novoand not from an adenomatous polyp having collapsed on itself.