Risk factors for small intestinal adenocarcinomas that are common in the proximal small intestine

The frequency of primary small intestinal adenocarcinoma is increasing but is still low. Its frequency is approximately 3% of that of colorectal adenocarcinoma. Considering that the small intestine occupies 90% of the surface area of the gastrointestinal tract, small intestinal adenocarcinoma is very rare. The main site of small intestinal adenocarcinoma is the proximal small intestine. Based on this characteristic, dietary animal proteins/lipids and bile concentrations are implicated and reported to be involved in carcinogenesis. Since most nutrients are absorbed in the proximal small intestine, the effect of absorbable intestinal content is a suitable explanation for why small intestinal adenocarcinoma is more common in the proximal small intestine. The proportion of aerobic bacteria is high in the proximal small intestine, but the absolute number of bacteria is low. In addition, the length and density of villi are greater in the proximal small intestine. However, the involvement of villi is considered to be low because the number of small intestinal adenocarcinomas is much smaller than that of colorectal adenocarcinomas. On the other hand, the reason for the low incidence of small intestinal adenocarcinoma in the distal small intestine may be that immune organs reside there. Genetic and disease factors increase the likelihood of small intestinal adenocarcinoma. In carcinogenesis experiments in which the positions of the small and large intestines were exchanged, tumors still occurred in the large intestinal mucosa more often. In other words, the influence of the intestinal contents is small, and there is a large difference in epithelial properties between the small intestine and the large intestine. In conclusion, small intestinal adenocarcinoma is rare compared to large intestinal adenocarcinoma due to the nature of the epithelium. It is reasonable to assume that diet is a trigger for small intestinal adenocarcinoma.     

小肠动力与影响因素的研究进展

小肠受特殊解剖位置以及检测手段的限制,小肠运动功能的研究相对滞后,尤其是对小肠MMC的病理生理功能缺乏全面的了解。研究证实小肠动力异常与细菌过度生长和慢传输性便秘等有关。十二指肠内酸和脂肪、葡萄糖的吸收对小肠动力均有影响。同时神经体液等因素对小肠动力也有调节作用。     

Diagnosis and treatment of small bowel diseases are advanced by capsule endoscopy and double-balloon enteroscopy

In 2001, new endoscopic procedures for the small bowel, capsule endoscopy (CE) and double-balloon enteroscopy (DBE), were introduced into regular clinical practice. These methods were significant breakthroughs for imaging examination of the small bowel. The methods have different characteristics with regard to their approach into the target organ; however, common to both is the feature of enabling rapid total observation of the small bowel. CE is the first safe, non-invasive well-tolerated procedure and can be performed in any condition. The examination time is about 8 h and the patient can spend the time freely. CE can demonstrate active bleeding or neoplasm in the small bowel, which other modalities cannot detect. DBE, which was developed by Yamamoto, employs two balloons combined with an overtube and allows deeper insertion into the small bowel, and can be a modality for examination of the entire small bowel with combined oral and anal approaches. This modality enables biopsy specimens to be taken, polyps to be resected and hemostatic procedures to be performed throughout the small bowel. The understanding of small bowel disease is being extended by using CE and DBE for diagnosis. CE is considered to be superior for the first examination of the small bowel and DBE is useful for detailed examination and endoscopic therapy. Further clinical study of unknown small bowel disorders using these two modalities and algorithms for the management of small bowel disorders are required.     

Diagnostische Evaluation der D��nndarmmotilit?t

Investigations of small bowel motility are performed relatively infrequently partly because of impaired accessibility of the small bowel. For diagnostic evaluation transit measurements and manometric techniques are generally available. Scintigraphy is regarded as the reference method for evaluation of small bowel transit but is rarely performed in Europe. Clinically, the lactulose hydrogen breath test is most frequently used for estimation of orocecal transit time. Apart from this radiological techniques can be used to roughly estimate small bowel transit. Capsule techniques and the lactulose-¹³C-ureide breath test represent potential alternatives. In contrast to transit measurements small bowel manometry reveals information on the contractile patterns of the small bowel and thus on pathophysiological mechanisms. However, small bowel manometry is relatively complex and labor-intensive and is therefore reserved for special indications and specialized centres.     

Hypothesis on the existence of an adenoma-carcinoma sequence in the small intestine

An analysis of a literature survey of 104 adenomas of the ampulla of Vater, 94 of the duodenum and 20 of the jejunum and ileum, as well as 735 carcinomas of Vater's ampulla, 180 carcinomas of the duodenum and 72 carcinomas of the jejunum and ileum, demonstrated, in spite of small case collectives, that there is probably a similar close relationship between adenomas and carcinomas in the small intestine, as in the large intestine. In adenomas of the small intestine signs of malignancy sometimes can be seen, as well as in some case of carcinoma of the small intestine rests of adenomas have been described. The age and sex distribution of the epithelial neoplasms of the small intestine permits an adenoma-carcinoma-sequence. The relative distribution of the adenomas over the different parts of the small intestine corresponds with that of the carcinomas. The adenomas and carcinomas of the small intestine in patients with adenomatosis coli have the same relationship to the neoplasms of the small intestine in patients without adenomatosis coli, as it is valid in the large intestine. The hypothesis of an adenoma-carcinoma-sequence in the small bowel with a great significance, which explains the results best, is therefore proposed. As the distribution of adenomas and carcinomas of the small bowel in patients with and without familial polyposis is equal, the theory is suggested, that the principle of the adenomatosis intestine disease is a general increase of the overall liability to adenomas in the large and small intestine.     

Adenomas and carcinomas of the small intestine in familial polyposis and Gardner syndrome--analysis of a literature survey

An analysis of 70 case records from the literature of patients with familial polyposis or Gardner syndrome and adenomas or carcinomas of the small bowel demonstrated that there is no difference between the neoplasms of the small bowel in familial polyposis or in Gardner syndrome. Between the adenomas and the carcinomas of the small bowel it was possible to show, that there exists a similar close relation as in the large intestine. In some carcinomas of the small bowel rests of adenomas can be observed. The peak incidence of small bowel adenomas is more than a decade earlier than that of carcinomas. The distribution of adenomas in the small bowel is quite similar to that of carcinomas. Therefore it can be supposed, that the significance of familial polyposis coli and Gardner syndrome for the importance of an adenoma-carcinoma-sequence in the large bowel is also existing in the small bowel.     

Pseudogastroparesis as a presentation of adenocarcinoma of the proximal jejunum

Establishing the presence of adenocarcinoma of the small bowel is exceedingly difficult. Survival is contingent on prompt diagnosis. We describe a patient with an atypical presentation of jejunal adenocarcinoma visualized via small bowel enteroclysis. She was referred with "gastroparesis," based on both a radionucleotide scan that revealed markedly delayed gastric emptying and a "normal" small bowel series.
A markedly abnormal scintigraphic study and a negative small bowel series does not exclude disease of the small intestine and should provide the impetus to further pursue the possibility of an obstructing lesion. The enteroclysis is a relatively safe and effective study in the preoperative diagnosis of small bowel tumors.     

Clinical utility of enteroclysis

The incidence of pathology in the small bowel is substantially lower than in the upper gastrointestinal tract or colon. This is fortunate since the small bowel, with its unique anatomy and remote location is the most difficult section of the gastrointestinal tract to study. Instillation of contrast into the small bowel lumen can be achieved by the oral route or by the more recently refined technique of small bowel intubation/infusion called enteroclysis. This brief review will focus on the clinical infusion indications for and efficacy of enteroclysis and the relative advantages of enteroclysis over oral methods of small bowel radiography.     

Small thymomas and myasthenia gravis: a poorly understood association

Myasthenia gravis (MG) is associated with about 20% of all patients with thymomas, but the occurrence in patients with small thymomas is rare. The pathogenetic relevance of these small thymomas for MG is poorly understood until now. We report on the clinical course of a 39-year-old female patient suffering from MG and undergoing thymectomy for a small thymoma and discuss the pathogenetic importance of small thymomas for MG.     

Introduction to small bowel tumors

The small bowel is a relatively infrequent site of malignancy in the gastrointestinal tract. The most common primary tumors of the small bowel are adenocarcinoma, lymphoma, neuroendocrine tumors, and gastrointestinal stromal tumors. However, as many as half of all small bowel tumors are metastatic. In general, the best chance for cure in patients with localized primary small bowel malignancy is surgical resection. The incidence of primary small bowel cancer is strikingly elevated in the genetic syndromes of familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, and Peutz–Jeghers syndrome. In the hope of prevention or early detection of cancer in patients with these disorders, experts have recommended surveillance of the small bowel in affected individuals. Historically, surveillance has been performed with small bowel radiography. However, in the past decade, video capsule endoscopy has largely replaced x-ray studies. Device-assisted enteroscopy, most notably double-balloon enteroscopy, has assumed an expanding role in the surveillance of these patients and in the endoscopic removal of premalignant lesions of the small bowel, such as adenomas and hamartomas.     

C基因型HBV较B基因型HBV易引起肝炎慢性化的机制

目的探讨HBVC基因型较B基因型易引起肝炎慢性化的机制。方法从GenBank分别下载C基因型和B基因型小S蛋白的氨基酸序列（即HBsAg），用CLustalW2．0生物软件分别比较C基因型和B基因型小S蛋白氨基酸序列的相似性；用神经网络的方法预测同基因型不同的小S蛋白氨基酸序列之间的T细胞表位的差异。结果通过分别比较C基因型和B基因型小S蛋白的氨基酸序列的相似性，C基因型小S蛋白的氨基酸序列之间的相似性为（90～100）％，B基因型小S蛋白的氨基酸序列之间的相似性为（94～100）％；同基因型不同的小S蛋白氨基酸序列之间的T细胞表位存在明显差异。结论C基因型小S蛋白的氨基酸序列之间较大的变异和同基因型不同的小S蛋白氨基酸序列之间的T细胞表位的差异可能是HBVC基因型较B基因型易引起肝炎慢性化的原因或部分原因。     

Inter-observer variations on interpretation of capsule endoscopies

OBJECTIVE: Capsule endoscopy is a novel investigation for diagnosing small bowel diseases. However, its interpretation is highly subjective and the potential variability may compromise its accuracy and reliability. Here we studied the potential inter-observer variations on the interpretation of capsule endoscopy. METHOD: Two residents and one specialist in gastroenterology independently reviewed 58 capsule endoscopy studies in the same sequential order. The gastric transit time, small bowel transit time, and the most significant small bowel lesion were independently recorded. The consensus transit time was determined by the joint review of the three gastroenterologists. The 'gold standard' for small bowel diagnoses was based on final surgical, endoscopic findings or consensus diagnosis. RESULTS: Clinically significant and relevant small bowel lesions were found in 32 (55%) cases by consensus review. The overall mean accuracy in determining gastric emptying time, small bowel transit time and small bowel lesion was 89%, 76% and 80%, respectively. There was a significant difference in the accuracy between the residents and specialist on small bowel transit time (P<0.05) and small bowel diagnosis (P<0.05). The mean kappa values on small bowel diagnosis among the three viewers was 0.56 (range, 0.52-0.59). Among various small bowel diagnoses, small bowel bleeding was more accurately identified than other pathology. CONCLUSIONS: Our results show that there is moderate degree of inter-observer discrepancies on the interpretation of capsule endoscopy. A second reading by an experienced viewer might improve the diagnostic accuracy of this investigation.     

Asymptomatic small intestinal ulcerative lesions: Obesity and Helicobacter pylori are likely to be risk factors

It is often difficult to explain why ulcerative lesions are found in the small intestine because there are no obvious aggressors such as gastric acid. In particular, the treatment of small intestinal ulcerative lesions in asymptomatic patients with no symptoms, normal physical examinations, and normal blood test findings is not well documented. According to a summary of capsule endoscopy studies in healthy subjects, approximately 10% of subjects have small intestinal mucosal breaks. The number of mucosal breaks in these instances is approximately 1-3. We examined small intestinal mucosal breaks in healthy subjects recruited from our past two studies. Mucosal breaks were observed in approximately 10% of subjects, and the average number was 0.24 ± 1.21. The number of mucosal breaks in the small intestine was correlated with body mass index and was significantly higher in Helicobacter pylori-infected subjects and higher in males. These results indicate that 1-2 small ulcerative lesions, such as erosions in the small intestine, can be considered to be in the normal range, and close examination is not required. It is assumed that a follow-up medical examination is required for such asymptomatic persons. The presence of many small ulcerative lesions or an unequivocal ulcer indicates an abnormality for which close examination is desired. However, in many cases, it is sufficient to scrutinize after detecting anemia, but it is difficult to make a judgment due to insufficient reports, and future studies are required.     

Endomyocardial biopsy diagnosis of small vessel disease: a clinicopathologic study

We reviewed the clinical history of 191 patients undergoing endomyocardial biopsy and correlated signs and symptoms of heart disease with the presence or absence of small vessel disease. Idiopathic congestive heart failure (78%), arrhythmia (35%), and chest pain (25%) were the most frequent indications for biopsy. Small vessel disease was noted in 61% of the biopsies (67% female, 56% male): 10% severe, 36% moderate, and 15% mild small vessel disease. Patients with hypertension were twice as likely to have small vessel disease than those without hypertension. Of the 27 females with hypertension, 85% had small vessel disease, 67% with either severe or moderate small vessel disease. Small vessel disease was almost twice as frequent in patients with chest pain compared to patients without chest pain. Chest pain was significantly more common in patients with severe small vessel disease than in those with normal small vessels. Of all patients with chest pain, 18% had severe small vessel disease; however, of 20 patients with severe small vessel disease, 45% had chest pain. This analysis suggests that small vessel disease seen in endomyocardial biopsy is more common in women and is related to hypertension. When severe, it is likely to be associated with atypical chest pain.     

The abdominal cocoon and an effective technique of surgical management.

The Abdominal Cocoon is a very rare cause of small bowel obstruction. It is caused by encapsulation of the small bowel by a fibrous membrane. This tropical disease, seen in young females, has also been reported in males. This is one of the largest series of the Abdominal Cocoon, with five new patients (3 males and 2 females) being reported. The traditional surgical treatment of choice is by lysis of adhesions. All patients in this case series had small bowel intubation done in addition to adhesiolysis. Although small bowel intubation is an established procedure for various causes of recurrent small bowel obstruction, to our knowledge this is the first report of its use in the management of the Abdominal Cocoon. We report our surgical technique in the management of this rare disease.     

Small bowel endoscopy and Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant inherited disease. It is clinically characterized by the development of gastrointestinal hamartomas, mainly located in the small bowel. These hamartomas are prone to complications such as intussusceptions, abdominal complaints and anaemia. Furthermore, patients are at increased risk for developing small bowel cancer. Therefore, regular surveillance of the small bowel is indicated. However, the optimal strategy for surveillance has not been determined yet. This review gives an overview of the different techniques that have been described to examine the small bowel of PJS patients. First, a number of radiologic and endoscopic imaging modalities with diagnostic value are discussed. Secondly, recently developed advanced endoscopy techniques are described that can serve both as a diagnostic and therapeutic tool in the surveillance of the small bowel. Finally, a recommendation is given how to apply these individual techniques for small bowel surveillance in a step-up approach.     

Small bowel neoplasia in coeliac disease

There is an increased risk of small bowel adenocarcinoma in patients with coeliac disease compared with the normal population. It has been suggested that adenocarcinoma of the small intestine in coeliac disease arises through an adenoma-carcinoma sequence but there has been only one reported case of a small bowel adenoma in a patient with coeliac disease. We report three additional cases of a small bowel adenoma in the setting of coeliac disease. In addition, four cases of small bowel adenocarcinoma are also reported, one of which was found adjacent to a jejunal villous adenoma. These cases emphasise the risk of the development of small bowel neoplasia for patients with coeliac disease and support the concept that small bowel adenocarcinoma in coeliac disease arises from adenomas.     

Radiological Investigation of the Small Intestine by Small Bowel Enema Technique

This paper records some experience with the Scott Harden technique of small intestinal intubation for performing small bowel enemas. It is particularly recommended for searching for obstructive or infiltrative lesions of the small intestine.