Recent advances in radiological and endoscopic techniques have enabled many flat or depressed colorectal neoplasms to be diagnosed. However, histological criteria for diagnosing colorectal cancer and adenoma are still being debated. The author studied whether or not immunohistochemical staining with PCNA could be used to indicate the grade of malignancy of flat or depressed colorectal neoplasms and obtained the following results. 1) In flat or depressed neoplasms, labeling index of PCNA correlated well with the histological grade of atypia, and PCNA positive cells were distributed quite diffusely towards the surface of mucosa in proportion to the histological grade of atypia. 2) Of 39 lesions of minute and flat or depressed neoplasms which correspond to Group 4 of general rules for clinical and pathological studies on cancer of colorectum, three lesions were similar to carcinoma in the PCNA labeling index and the distribution pattern of PCNA positive cells, and 15 were similar to adenoma in the PCNA labeling index. This suggested that lesions diagnosed as Group 4 by HE stain were morbid but varied in malignancy. 3) Therefore, the immunohistochemical method using PCNA seems to be valuable as a supportive diagnostic measure in borderline lesions that are considered to correspond to Group 4.

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We have established a new rat model using an originally devised occlusion tool made from a plastic cylinder, in which we can easily give incomplete obstruction to the rat rectum without damaging the mesenterium, and also remove the obstruction after a certain period of time. The severity of colonic damage induced by incomplete obstruction of the rectum was increased with the progression of proximal intestinal distention. Even 1 day after the obstrucitve procedure, various degrees of epithelial exfoliation on the proximal mucosa of the obstuction site and both mucosal and submucosal edema was observed. Until 3 days after obstruction, the damage of the colonic wall progressively increased, and all animals developed macroscopically visible ulcers and inflammation frequently associated with the pseudomembrane on the ulcer floor. Following incomplete obstruction, the ulcerative lesion was aggravated as the oral side of the colon was delated, and a marked positive correlation was found between the perimeter of the dilated colon and the total area of each ulcerative lesion. The intestinal wall blood flow started decrease just after the beginning of obstruction and continued to decrease until the 5th day. There was a marked negative correlation between the blood flow and the intestinal perimeter or the blood flow and the ulcer area. After removing the obstruction, the levels of the delated intestinal perimeter and the ulcer area were significantly reduced, as compared with those in the group of rats given a 5-day-obstruction only. The blood flow significantly recovered 1 week after .removal of the obstruction. Proliferative activity of mucosal cells in the obstructive colon was remarkably increased during the obstruction periods of I to 5 days. There was a significant negative correlation between the labeling index (cell proliferative activity) and the blood flow.
These results suggest that an increase in intracolonic pressure, as reflected in intestinal dilatation, causes ischemia in the colonic mucosa, thereby leading to the development and aggravation of ulcerative lesions.

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In BALB/C mice, colon 26 was used as a model for hepatic micrometastasis of mouse transplantable colorectal cancer, and we injected intraportally 5-fluorouracil ( 5-FU), uracil and degradable starch microspheres ( DSM). The levels of 5-FU and uracil in the liver and serum were determined, and their inhibitory effect on hepatic metastasis was studied. 5-FU was injected at a dose of 30mg/kg body weight, uracil at an equal dose as well as 4 or 8 times higher than the dose of 5-FU in molar ratio, and DSM at a dose of 5mg/kg body weight. In the group simultaneously given 5-FU and uracil at a dose 8 times the molar ratio plus DSM, the hepatic level of 5-FU was high, but the serum 5-FU level did not increase.
The efficacy of this regimen in preventing hepatic metastasis was superior due to the hepatic accumulation of 5-FU and uracil, which, with the aid of DSM, retarded the breakdown of 5-FU. These findings suggest it may be possible to suppress the hepatic metastasis of colorectal cancer clinically by applying this method.

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The purpose of this study was to evaluate the influence of formalin fixation periods and the enhancement of immunoreactivity by exposure of tissue sections to microwaves in p 53 immunostaining. Tissues of 3 colon cancers were fixed in formalin from 24 hours to 2 weeks, and embedded in paraffin. The archival materials were 21 colorectal tumors which were fixed in formalin within 48 hours and 19 colorectal tumors of unknown fixation periods. We compared immunohistochemically these microwave-treated sections and serially cut untreated sections. p 53 immunoreactivity was obviously decreased by 2-week formalin fixation and all of these cases were retrieved by exposure of tissue sections to microwaves. Although the results of immunostaining of formalin-fixed tissues within 48 hours were not changed, the positive rates of unknown fixation period tissues were improved. Therefore, it is concluded that the periods of fixation should be within 48 hours in p 53 immunostaining of formalin-fixed tissues and the antigen retrieval based on exposure of tissue sections to microwaves may be assessment of p 53 overexpression in archival materials.

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We report a case of a giant lipoma in the descending colon discovered in incarceration of the anus during tumor extroction. A 75-year-old woman was admitted to our hospital complaining of anal bleeding with discomfort. We could observe and palpate a tumor having a yellowish, elastic soft, smooth surface which was round outside of the anus. The tumor was so easy to reduce with manipulation that we could not observe or palpate it after the reduction. We clinically diagnosed this tumor to be a lipoma of the descending colon by means of examinations. Initially, we attempted to extirpate the tumor using a colonic fiberscope, but it was impossible because of the thickness of the tumor's stalk. Therefore we performed successful partial resection of the descending colon in open surgery. The resected tumor size was 9.5×6.5cm, and its stalk was 2.5cm in diameter. The cross section observed macroscopically was fatty tissue, and pathological findings confirmed increased mature fatty tissue. This tumor was diagnosed as a lipoma of the colon. The colonic fiberscopy and computer tomography were effective in the diagnosis of the tumor.

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We report a case of lipoma of the sigmoid colon which was passed following barium enema study. A 37-year-old male experienced occasional hemorrhage from the anus in late September 1993 and visited our clinic on October 20, 1993. Since digital exploration revealed nothing, sigmoidoscopy was performed on the same day and a smooth pedunculated spherical mass in the midsigmoid colon was revealed. It was about 4 cm in diameter and associated with redness. On October 25, contrast enema was performed after colon preparation by Brown's modified method. The nest day, the mass was eliminated with a small amount of melena. It was histologically determined to be a lipoma composed of proliferated mature adipose tissue which contained no mucous membrane.

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This report describes that the balloon catheter, inserted into the upper anastomotic, region through the anus for elimination of intestinal contens with continuous low negative pressure aspiration of the pelvic drain, is efficacious in order to rest and clean the anastomotic region using coservative therapy of anastomotic leakage after low anterior rectal resectinon (LAR).
Five cases with leakage after LAR were recently investigated.
All of them had a clinically slight to moderate fever, abdominal pain and stool evacuation from the pelvic space, and leakage of contrast material from the anastomotic region was revealed by gastrografin enema.
Stool elimination from the balloon catheter was 200-300ml/day maximally in the cases of good elimination, and discharge aspirated from the pelvic drain was markedly decreased.
The duration needed for recovery of leakage was 12.5 days and fasting time was 15.3 days on the average, these were shorter than when of no balloon catheter was interposed.
The balloon catheter inserted into the upper anastomotic region through the anus is efficacious for the recovery of anastomotic leakage.
This technigue may be equal to establishing an artificial anus, provided it is well controlled.

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The patient was a 70-year-old female, who experienced right hemicolectomy for transverse colon cancer six years ago. This time, she had rectal cancer when admitted to our hospital and low anterior resection was perfomed. She complained of sudden left lateral abdominal pain after 3 P. O. D. By Barium enema, a diagnosis of perforated gangrenous-type ischemic colitis and abdominal fistula formation on descending colon was made. In spite of conservative therapies for several weeks, severe stenosis of the descending colon remained. Descending colectomy was performed 4 mouths after the first operation. The resected specimen showed a thickened bowel wall and marked irregularity of the mucosa accompanied by ulcers. After the operation, the patient was discharged from the hospital.

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The incidence of lipoma appearance is relatively high among nonepithelial tumors of the large intestine, but it is rarely found on a routine basis. We have experienced a case of lipoma of the sigmoid colon along with ileus.
A 46-year-old man was admitted to our hospital because of lower abdominal pain and nausea. Abdominal plain X-ray showed a dilated large intestine, and a long tube was inserted. Ba -enema and colonoscopy revealed an elastic -soft submucosal tumor with erosion. The CT value of tumor was -100 Hounsfield units, identical to adipose tissue. From these findings, the tumor was diagnosed as lipoma of the sigmoid colon. A partial colectomy was performed, and the resected tumor was 3.0×3.2×2.8cm.
Histopathologically it was a typical submucosal lipoma covered with normal mucosa of the large intestine and hyperplasia of adipose tissue.
From 1987 to 1994, we have experienced 6 cases of lipoma of the large intestine including 2 males and 4 females. We performed the resection of lipoma endoscopically for 5 patients and operatively for 1 patient.

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From 1982 to 1993, we treated 344 cases of primary colorectal cancer. Of these patients, 17 cases (4.9%), 9 males and 8 females, were less than 40 years of age (younger group) and 69 cases(20.1%) were over 75 years of age (older group). We compared clinico-pathological features of these two groups.
The male-female ratio of the younger group, was smaller than that of the older group. Lymph node metastasis, hepatic metastasis and peritoneal dissemination were similar in both growps, and patients in the younger group had a tendency to develop more infiltrative growth and to have greater depth of the tumor and more blood vessel invasion than the older group.
Early diagnosis of colorectal cancer and a possible curative surgical procedure are considered to be important.

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Colorectal cancers of 174 patients aged 75 years and over (elderly group) were selected and compared with those of 1181 patients aged 74 years and under (control group) from January 1983 to December 1992. The elderly group demonstrated the following tenden-cies : (1) the proportion al differences of the clinicopathological stages were in significant, (2) a high rate of preoperative complication (p<0.01), (3) a high rate of group 1 lymph node dissection and a low rate of group 3 lymph node dissection (p<0.01), (4) a low rate of AR and a high rate of Hartmann's operation ( p<0.01 ) were found in patients with rectal cancers, (5) the rate differences of resection and curative resection were in significant, (6) a high rate of postoperative complications (p<0.01), including postoperative pneumonia which vequives utmost cave, and(7)the survival rate differences were insigniffcant.

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