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Biomedical subjects

B C Morson

Publications and source records attributed to B C Morson.

At least 73 records · Page 4Linked to original sources

Invasion of veins by carcinoma of rectum: method of detection, histological features and significance.

Histopathological material from operation specimens of rectal adenocarcinoma was reviewed and invasion of veins identified in 51.9% of 703 cases. The extent of venous invasion, thickness of the walls of invaded veins and various other histological features were examined in detail. By follow-up studies recurrence rates, incidence of distant metastases and corrected 5-year survival rates were obtained; correlation with the histopathological results showed that invasion of extramural and thick-walled veins is associated with a poor prognosis independent of the degree of differentiation of the adenocarcinoma. Prognosis is not significantly related to the presence of necrosis of intravenous tumour and a clearly defined stroma in the intravenous growth all appear to exert a protective influence on patient survival. Whereas permeation of capillaries in vein walls, the presence of loose clumps of tumour cells in veins and direct contact between tumour cells and venous blood appear to adversely affect survival. Venous invasion is shown to be related to local invasiveness of rectal carcinoma. Suggested modes of venous spread and interaction with host tissues are proposed, with implications for general attitudes to the spread of cancer and metastasis.

Adenocarcinoma↗

Pre-operative computed tomography of carcinoma of the rectum.

Fifty-two patients with carcinoma of the rectum under-went computed tomography (CT) in the immediate preoperative period. CT was used in order to assess extrarectal tumour spread. The resected specimen was staged by the pathologist who subdivided spread in continuity beyond the bowel wall into slight, moderate or extensive. In 21 out of 23 patients with no or slight extrarectal local spread CT showed normal perirectal fat. Extrarectal spread was demonstrated by CT in eight of the nine patients found to have extensive local spread. This was seen to be circumferential in the only two patients with inoperable tumors. CT identified discrete nodal enlargement in seven of the 18 patients with histologically involved lymph nodes. CT may help the less experienced surgeon, especially when he is not confident of his findings at digital examination. CT allows assessment of high rectal tumours which cannot be examined digitally. It may play a role where a tumour with extensive local spread is clinically suspected and confirmation is needed before preoperative radiotherapy is given.

Humans↗

The clinical significance of invasion of veins by rectal cancer.

A histopathological study of 703 surgical specimens from patients with adenocarcinoma of the rectum revealed invasion of veins by primary growth in almost 52 per cent. Follow-up studies on the patients showed that the corrected 5-year survival rate was significantly worse and liver metastases developed more frequently when venous invasion was present. Invasion of extramural veins was particularly significant whereas spread confined to intramural veins was less important. Invasion of large (thick-walled) veins was of greater consequence than invasion of small (thin-walled) veins and spread into thick-walled extramural veins had the greatest adverse influence of all. Venous spread of tumour takes place in parallel with local spread as measured by the Dukes' stage but exerts an influence on prognosis independent of the Dukes' stage. Similarly, vein invasion parallels the number of lymph node metastases but appears to exert an independent influence on prognosis. Observation of venous spread provides a precise assessment of the likely behaviour of rectal carcinoma and supplements, but does not replace indices such as the Dukes' stage or the number of lymph node metastases in routine use. The implications for surgical technique and management are discussed.

Adenocarcinoma↗

Metaplastic polyps and polyposis of the colorectum.

Five hundred and fifty-four colorectal metaplastic polyps have been studied histologically. Whilst most lesions were small and sessile, 16.1% measured greater than 0.5 cm in diameter and 0.9% were greater than 1 cm. The larger polyps were frequently pedunculated and occasionally showed a tubulo-villous or villous pattern. A structural similarity between the larger metaplastic polyps and colorectal adenomas is illustrated and the importance of the distinction of metaplastic from dysplastic epithelium in the differentiation of these lesions is stressed. Other unusual features of metaplastic polyps are described. Evidence is given to suggest that males have a greater propensity to develop metaplastic polyps than females. A search for men adenomas, but relatively frequent (20.8%) in juvenile polyps. Finally, seven patients with multiple metaplastic polyps of the colorectum are described, in whom a diagnosis of adenomatous polyposis had been made at some stage in their management. Six of the seven patients were males and the mean age at presentation was 37.4 years. Larger metaplastic polyps were frequent in these cases. The necessity for histological confirmation in all cases of intestinal polyposis is stressed, and the possibility that 'metaplastic polyposis' is a pathological entity is discussed.

Adenoma↗

Precancerous conditions and epithelial dysplasia in the stomach.

A distinction can be made between a precancerous condition and a precancerous lesion. The former is a clinical state associated with a significantly increased risk of cancer, whereas a precancerous lesion is a histopathological abnormality in which cancer is more likely to occur than in its apparently normal counterpart. Up to the present time atrophic gastritis, gastric ulcer, pernicious anaemia, gastric stumps, gastric polyps, and Ménétrier's disease have all been considered as precancerous conditions and lesions of the stomach. Of these, only atrophic gastritis, pernicious anaemia, gastric stumps, and certain types of gastric polyp can now be regarded as having any really significant malignant potential. The precancerous lesion common to these is epithelial dysplasia which can occur in ordinary (foveolar) gastric epithelium as well as in intestinal metaplasia. The criteria for grading dysplasia in gastric epithelium into mild, moderate, and severe grades are given, and attention is drawn to the problems of differentiating inflammatory or regenerative change from mild dysplasia and intramucosal carcinoma from severe dysplasia. The clinical and epidemiological implications of gastric dysplasia are discussed with suggestions for further research.

Anemia, Pernicious↗

Squamous carcinoma of the colorectum and its genesis.

A case of pure aquamous carcinoma of the rectum is presented, and the literature reviewed. Squamous carcinomas of the colorectum are rare tumours which have clinicopathological features in common with adenocarcinomas. Evidence is presented to support the proposal that most tumours of the large intestine that consist partly or completely of squamous elements arise from areas of squamous differentiation in pre-existing adenomas. The pathogenesis of squamous carcinoma and adenosquamous carcinoma appears to be similar to that of adenocarcinoma.

Adenocarcinoma↗

Colonic adenomas--a colonoscopy survey.

A colonoscopy survey of 620 patients with 1049 colon adenomas showed a predominantly left-sided distribution (77%). Of these lesions 97% were amenable to endoscopic removal or ablation. Sixty per cent of patients presented with rectal bleeding as their major symptom. There was agreement between radiology and colonoscopy in only 62% of patients, as many of the studies were single contrast barium enemas, performed before referral. Forty-eight per cent of adenomas in our series were less than 1.0 cm in diameter. Of the larger adenomas (greater than 2.0 cm in diameter) 66% were situated in the sigmoid colon, and of those containing invasive carcinoma (4.8% of the total) an even higher percentage (94%) were in the sigmoid and low descending colon. With increasing polyp size, there was a greater predominance of villous elements and this was associated with a higher risk of malignant change than the more frequent and generally smaller tubular adenoma. Local colonoscopic excision alone is sufficient treatment for adenomas with malignant change unless they are poorly differentiated histologically and providing adequate resection is demonstrated. Twenty-eight patients treated in this way are alive without recurrence at periods from six to 62 months. Although 65% of patients had only one adenoma, and 90% three or less, there is a risk of developing other benign and malignant colon neoplasms and careful follow-up is required.

Adenoma↗

The granuloma in Crohn's disease.

The number of granulomas in sections of bowel involved by Crohn's disease has been counted and related to length of previous history, treatment with steroids, site of involvement, and the subsequent course of the disease. It was found that a high content of granulomas predicted a good prognosis in the large bowel and anus, but was of no prognostic significance in the small bowel. A large regional variation in granuloma counts was observed from an average of 1 per section in the small bowel to 6 in the colon, 18 in the rectum, and 36 in the anus. Those patients with a long clinical history showed a low granuloma content. The findings are consistent with the view that the granuloma represents an adaptive mechanism for the removal or localisation of the causative agent of Crohn's disease.

Anus Diseases↗

Value of sigmoidoscopy and biopsy in detection of carcinoma and premalignant change in ulcerative colitis.

Of 111 carcinomas developing in 73 patients with ulcerative colitis, 46 (41.5%) arose in the rectum where they are directly accessible to sigmoidoscopy. Fifty-eight per cent of single carcinomas developed in the rectum. The extent and frequency of rectal dysplasia was assessed by examining slides of rectal mucosa with an eyepiece micrometer. Slides from 46 patients with carcinoma and 22 patients with dysplasia but no carcinoma in whom proctectomy or proctocolectomy had been carried out were examined by this method. Thirteen of 15 patients with carcinoma of the colon (87%) and 21/22 patients (95%) with large bowel dysplasia showed evidence only of rectal dysplasia. However, there was marked variability in the proportion of dysplastic rectal mucosa even in those patients with rectal carcinoma, while in some patients dysplasia was limited to a small focus. Because of the possibility of false negative biopsies due to sampling error, multiple biopsies should be taken to detect dysplasia. Their state should be recorded and deliberately varied at subsequent visits. Careful sigmoidoscopy and multiple biopsies in this study had potential value as an aid in the detection of 85-90% of all carcinomas. In practice the figure would almost certainly be lower due to intrinsic bias (see discussion) so that, although regular sigmoidoscopy and biopsy would be of great value when colonoscopy is not available, the latter should be included in any long-term programme of carcinoma prevention.

Biopsy↗

Ileal adenomas after colectomy in nine patients with adenomatous polyposis coli/Gardner's syndrome.

Adenomas of the ileal mucosa are an uncommon finding in adenomatous polyposis coli/Gardner's syndrome. We report 9 patients who were found to have ileal adenomas 1 yr 11 mo to 25 yr 11 mo after colectomy. The ileal adenomas occurred proximal to an ileorectal anastomosis in 7 patients, both proximal to a cecoproctostomy and later proximal to an ileostomy in 1 patient, and in an ileostomy in 1 patient. The cases confirm that ileal mucosa is susceptible to adenoma formation in adenomatous polyposis coli/Gardner's syndrome and thus provide additional evidence that adenomas are not confined to the colon in these patients. In addition, the findings in the cases suggest that the ileal adenomas developed after colectomy. Thus, our cases suggest that the small intestine should be studied for the presence of adenomas after colectomy with either ileoproctostomy or ileostomy, as well as before resection. On the other hand, aggressive management does not seem warranted as carcinoma of the jejunum and ileum has been reported only rarely.

Adult↗

Aetiology of adenoma--carcinoma sequence in large bowel.

A hypothesis, based on epidemiological and histopathological data, is proposed to account for the aetiology of colorectal adenomas and carcinomas. Adenomas are initially caused by an environmental agent which acts on the colorectal cells of adenoma-prone persons, a further environmental agent causes small adenomas to grow, and a carcinogen causes malignancy in a high proportion of large adenomas.

Adenoma↗

The rectal biopsy appearances in Salmonella colitis.

Rectal biopsies were examined from 22 patients with Salmonella infection of food-poisoning type and from seven patients with inflammatory bowel disease and coincidental Salmonella infection. In the former group the changes observed were mucosal oedema with acute inflammation of varying severity but with preservation of the crypt architecture. Crypt abscesses were present in a few cases but were usually localized in the crypt and mucus depletion only occurred with severe inflammation. These features are not specific and are similar to those seen in other types of infective colitis such as Shigella dysentery, gonococcal proctitis and amoebic colitis. In the majority of cases of infective colitis the appearances are usually sufficiently distinctive, however, to distinguish them from those seen in ulcerative colitis and Crohn's disease. The changes in the biopsies from the seven patients with coincidental Salmonella infection were in general those of the underlying idiopathic inflammatory bowel disease.

Adolescent↗