Colonic duplication in adults: Report of two cases presenting with rectal bleeding

Gastrointestinal duplication is an uncommon congenital abnormality in two-thirds of cases manifesting before the age of 2 years. Ileal duplication is common while colonic duplication, either cystic or tubular, is a rather unusual clinical entity that remains asymptomatic and undiagnosed in most cases. Mostly occurring in pediatric patients,colonic duplication is encountered in adults only in a few cases. This study reports two cases of colonic duplication in adults. Both cases presented with rectal bleeding on admission. The study was focused on clinical, imaging,histological, and therapeutical aspects of the presenting cases. Gastrografin enema established the diagnosis in both cases. The cystic structure and the adjacent part of the colon were excised en-block. The study implies that colonic duplication, though uncommon, should be included in the differential diagnosis of rectal bleeding.

Clinical and genetic characteristics of Chinese hereditary nonpolyposis colorectal cancer families

AIM： To analyze the clinical characteristics of Chinese hereditary nonpolyposis colorectal cancer （HNPCC） families and to screen the germline mutations of human mismatch repair genes hMLH1 and hMSH2 in the probands. METHODS： Thirty-one independent Chinese HNPCC families were collected in Zhejiang Province. All of them met Chinese HNPCC criteria. Clinical data about patient gender, site of colorectal cancer, age of onset, history of multiple colorectal cancer, associated extracolonic cancer were recorded. PCR and denaturing high performance liquid chromatography （DHPLC） were employed to screen the mutations. Sequencing analysis was used to find out the exact mutation site and characteristics of the samples showing abnormal DHPLC profiles. RESULTS： One hundred and thirty-six malignant neoplasms were found in 107 patients including 14 multiple cancers. One hundred and six of the 136 neoplasms （77.9%） were diagnosed as colorectal cancer, with an average age of onset at 48.57 ±29.00 years. Gastric cancer was the most common extracolonic cancer （10.3%） in these families. Twenty-three different sequence variations in hMLHI and hMSH2 genes were detected in these 17 families. Fifteen sequence variations were located in the exons, including 5 SNPs, 3 silent mutations, 3 missense mutations, 2 nonsense mutations and 2 frameshift mutations. The latter seven mutations seemed to be pathogenic. CONCLUSION： Germline mutations of hMLH1 and hMSH2 genes are identified in about one-third HNPCC kindreds fulfilling Chinese HNPCC criteria. Chinese HNPCC families have some particular clinical characteristics, such as a left-sided predominance, less synchronous or metachronous colorectal cancer, and frequent occurrence of gastric cancer.

Prognostic value of lateral lymph node metastasis for advanced low rectal cancer

AIM： To evaluate the risk factors for lateral lymph node metastasis in patients with advanced low rectal cancer, in order to make the effective selection of patients who could benefit from lateral lymph node dissection, as well as the relationship of lateral lymph node metastasis with local recurrence and survival of patients with advanced low rectal cancer. METHODS： A total of 96 consecutive patients who underwent curative surgery with lateral pelvic lymphadenectomy for advanced lower rectal cancer were retrospectively analyzed. The relation of lateral lymph node metastasis with clinicopathologic characteristics, local recurrence and survival of patients was identified. RESULTS： Lateral lymph node metastasis was observed in 14.6% （14/96） of patients with advanced low rectal cancer. Lateral lymph node metastasis was detected in 10 （25.0%） of 40 patients with tumor diameter ≥ 5 cm and in 4 （7.1%） of 56 patients with tumor diameter 〈 5 cm. The difference between the significant （X^2 = 5.973, P = two groups was statistically 0.015）. Lateral lymph node metastasis was more frequent in patients with 4/4 diameter of tumor infiltration （7 of 10 cases, 70.0%）, compared with patients with 3/4, 2/4 and 1/4 diameter of tumor infiltration （3 of 25 cases, 12.0%; 3 of 45 cases, 6.7%; 1 of 16 cases, 6.3%） （X^2 = 27.944, P = 0.0001）. The lateral lymph node metastasis rate was 30.0% （9 of 30 cases）, 9.1% （4 of 44 cases） and 4.5% （1 of 22cases） for poorly, moderately and well-differentiated carcinoma, respectively. The difference between the three groups was statistically significant （X^2 = 8.569, P = 0.014）. Local recurrence was 18.8% （18 of 96 cases）, 64.3% （9 of 14 cases）, and 11.0% （9 of 82 cases） in patients with advanced low rectal cancer, in those with and without lateral lymph node metastasis, respectively. The difference between the two groups was statistically significant （X^2 = 22.308, P = 0.0001）. Kaplan-Meier survival analysis showed significant improvements in median survival （80.9 ± 2.1 m, 95% CI： 76.7-85.1 m vs 38 ± 6.7 m, 95% CI： 24.8-51.2 m） of patients without lateral lymph node metastasis compared with those with lateral lymph node metastasis （log-rank, P = 0.0001）. CONCLUSION： Tumor diameter, infiltration and differentiation are significant risk factors for lateral lymph node metastasis. Lateral pelvic lymphadenectomy should be performed following surgery for patients with tumor diameter ≥ 5 cm. Lateral lymph node metastasis is an important predictor for local recurrence and survival in patients with advanced low rectal cancer.

Identification of Lynch syndrome: How should we proceed in the 21^(st) century?

Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common form of hereditary colorectal cancer. Although great advances in the understanding of its molecular basis have taken place in the last decade, optimal selection of individuals for HNPCC genetic testing remains controversial. This is especially relevant since colonoscopy has been proven effective for reducing colorectal cancer incidence and mortality in individuals at-risk for this disorder. In this manuscript, we summarize the most significant contributions to this important issue that have appearedin the last few years.

Management of recurrent rectal cancer:A population based study in greater Amsterdam

AIM： To analyze, retrospectively in a populationbased study, the management and survival of patients with recurrent rectal cancer initially treated with a macroscopically radical resection obtained with total mesorectal excision （TME）. METHODS： All rectal carcinomas diagnosed during 1998 to 2000 and initially treated with a macroscopically radical resection （632 patients） were selected from the Amsterdam Cancer Registry. For patients with recurrent disease, information on treatment of the recurrence was collected from the medical records. RESULTS： Local recurrence with or without clinically apparent distant dissemination occurred in 62 patients （10%）. Thirty-two patients had an isolated local recurrence. Ten of these 32 patients （31%） underwent radical re-resection and experienced the highest survival （three quarters survived for at least 3 years）. Eight patients （25%） underwent non-radical surgery （median survival 24 rno）, seven patients （22%） were treated with radio- and/or chemotherapy without surgery （median survival 15 mo） and seven patients （22%） only received best supportive care （median survival 5 too）. Distant dissemination occurred in 124 patients （20%） of whom 30 patients also had a local recurrence. The majority （54%） of these patients were treated with radio- and/or chemotherapy without surgery （median survival 15 mo）. Twenty-seven percent of these patients only received best supportive care （median survival 6 mo）, while 16% underwent surgery for their recurrence. Survival was best in the latter group （median survival 32 mo）. CONCLUSION： Although treatment options and survival are limited in case of recurrent rectal cancer after radical local resection obtained with TME, patients can benefit from additional treatment, especially if a radical resection is feasible.

Complementary analysis of microsatellite tumor profile and mismatch repair defects in colorectal carcinomas

Microsatellite instability (MSI) is a prognostic factor and a marker of defi cient mismatch repair (MMR) in colorectal adenocarcinomas (CRC). However, a proper application of this marker requires understanding the following: (1) The MSI concept: The PCR approach must amplify the correct locus and accurately identify the microsatellite pattern in the patient’s normal tissue. MSI is demonstrat- ed when the length of DNA sequences in a tumor differs from that of nontumor tissue. Any anomalous expansion or reduction of tandem repeats results in extra-bands normally located in the expected size range (100 bp, above or below the expected product), differ from the germline pattern by some multiple of the repeating unit, and must show appropriate stutter. (2) MSI mechanisms: MMR gene inactivation (by either mutation or protein down-regulation as frequently present in deep CRC com- partments) leads to mutation accumulation in a cell with every cellular division, resulting in malignant transforma- tion. These mechanisms can express tumor progression and result in a decreased prevalence of aneuploid cells and loss of the physiologic cell kinetic correlations in the deep CRC compartments. MSI molecular mechanisms are not necessarily independent from chromosomal in- stability and may coexist in a given CRC. (3) Because of intratumoural heterogeneity, at least two samples from each CRC should be screened, preferably from the su- perfi cial (tumor cells above the muscularis propria) and deep (tumor cells infi ltrating the muscularis propria) CRC compartments to cover the topographic tumor hetero- geneity. (4) Pathologists play a critical role in identify- ing microsatellite-unstable CRC, such as occur in young patients with synchronous or metachronous tumors or with tumors showing classic histologic features. In these cases, MSI testing and/or MMR immunohistochemistry are advisable, along with gene sequencing and genetic counseling if appropriate. MSI is an excellent functional and prognostically useful marker, whereas MMR immuno- histochemistry can guide gene sequencing.

Functional activity of the rectum:A conduit organ or a storage organ or both?

AIM： To investigate whether the degree of rectal distension could define the rectum functions as a conduit METHODS： Response of the rectal and anal pressure to 2 types of rectal balloon distension, rapid voluminous and slow gradual distention, was recorded in 21 healthy volunteers （12 men, 9 women, age 41.7 ± 10.6 years）. The test was repeated with sphincteric squeeze on urgent sensation. RESULTS： Rapid voluminous rectal distension resulted in a significant rectal pressure increase （P 〈 0.001）, an anal pressure decline （P 〈 0.05） and balloon expulsion. The subjects felt urgent sensation but did not feel the 1^st rectal sensation. On urgent sensation, anal squeeze caused a significant rectal pressure decrease （P 〈 0.001） and urgency disappearance. Slow incremental rectal filling drew a rectometrogram with a ＂tone＂ limb representing a gradual rectal pressure increase during rectal filling, and an ＂evacuation limb＂ representing a sharp pressure increase during balloon expulsion. The curve recorded both the ist rectal sensation and the urgent sensation. CONCLUSION： The rectum has apparently two functions： transportation （conduit） and storage, both depending on the degree of rectal filling. If the fecal material received by the rectum is small, it is stored in the rectum until a big volume is reached that can affect a degree of rectal distension sufficient to initiate the defecation reflex. Large volume rectal distension evokes directly the rectoanal inhibitory reflex with a resulting defecation.

Gastrointestinal Stromal Tumors in the Rectum

OBJECTIVE To investigate the clinical and pathologic features of rectal gastrointestinal stromal tumors （GIST） and to evaluate their reasonable management. METHODS The clinical and pathological data for 19 patients with rectal GIST over the past 19 years were studied retrospectively. RESULTS The diagnosis of the 19 cases was identified by surgery and pathology. All the rectal GISTs were spindle cell type with immunohistochemical analysis showing positive reactivity for CD117 （100%） and CD34 （73.7%）. There were 4 cases of high risk, 3 cases of intermediate risk, 5 cases of low risk and 7 cases of very low risk of aggressive behavior in this study. CONCLUSION Rectal GIST, without specific symptoms in the early stage, has a low incidence and usually shows low risk of aggressive behavior. It is difficult to produce an accurate pathological diagnosis before operation and it is difficult to decide whether to save the sphincter before or during operation. Reasonable initial treatment includes trans-anal local resection as the best recommend management of low risk submucosal rectal GIST （〈3.0 cm）.

直肠肛管损伤13例诊治分析

目的:探讨直肠肛管损伤的诊断和治疗方法。方法:回顾性总结1997-07/2009-07收治的直肠肛管损伤患者13例。结果:行直肠损伤修补,转流性结肠造瘘8例,单纯修补肠壁,骶前引流3例,肛管会阴部清创缝合局部引流2例。治愈12例,死亡1例。结论:及时、正确的诊断和早期清创,修补破损,粪便转流及局部引流是提高直肠肛管损伤疗效的关键。