Colorectal tumours and pit pattern

Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps

AIM

To identify the feasibility of the narrow-band imaging (NBI) method compared with that of conventional colonoscopy and chromoendoscopy for distinguishing neoplastic and nonneoplastic colonic polyps.

METHOD

This study enrolled consecutive patients who underwent colonoscopy using a conventional colonoscope between January and February 2006 at Chang-Gung Memorial Hospital, Linkou Medical Center, Taiwan. These 78 patients had 110 colorectal polyps. During the procedure, conventional colonoscopy first detected lesions, and then the NBI system was used to examine the capillary networks. Thereafter indigo carmine (0.2%) was sprayed directly on the mucosa surface prior to evaluating the crypts using a conventional colonoscope. The pit patterns were characterized using the classification system proposed by Kudo. Finally, a polypectomy or biopsy was performed for histological diagnosis.

RESULTS

Of the 110 colorectal polyps, 65 were adenomas, 40 were hyperplastic polyps, and five were adenocarcinomas. The NBI system and pit patterns for all lesions were analyzed. For differential diagnosis of neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic) polyps, the sensitivity of the conventional colonoscope for detecting neoplastic polyps was 82.9%, specificity was 80.0% and diagnostic accuracy was 81.8%, significantly lower than those achieved with the NBI system (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%) and chromoendoscopy (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%). Therefore, no significant difference existed between the NBI system and chromoendoscopy during differential diagnosis of neoplastic and nonneoplastic polyps.

CONCLUSION

The NBI system identified morphological details that correlate well with polyp histology by chromoendoscopy.

Pit patterns in rectal mucosa assessed by magnifying colonoscope are predictive of relapse in patients with quiescent ulcerative colitis

BACKGROUND

Relapse of ulcerative colitis is difficult to predict by routine colonoscopy. A high-resolution video-magnifying colonoscope with chromoscopy enables the observation of colorectal mucosal pit patterns.

AIMS

To investigate the association of pit patterns as assessed by magnifying colonoscopy (MCS) with histological inflammation and mucosal chemokine activity in patients with quiescent ulcerative colitis, and to prospectively analyse the prognostic factors that may predict exacerbations.

METHODS

MCS was performed in 113 patients with ulcerative colitis in remission. Pit patterns in the rectal mucosa were classified into four MCS grades on the basis of size, shape and arrangement. Mucosal interleukin (IL) 8 activity was measured in biopsy specimens of rectal mucosa and the specimens were assessed for histological disease activity. The patients were then followed until relapse or for a maximum of 12 months. Multivariate survival analysis was carried out to determine the independent predictors of clinical relapse.

RESULTS

A positive correlation was identified between MCS grade, histological grade (p = 0.001) and mucosal IL8 activity (p<0.001). Multivariate proportional hazard model analysis showed that MCS grade was a significant predictor of relapse (relative risk 2.06, p = 0.001). Kaplan-Meier estimate of relapse during 12 months of follow-up was found to increase with increasing MCS grade, with values of 0% for grade 1, 21% for grade 2, 43% for grade 3 and 60% for grade 4.

CONCLUSION

MCS grading is associated with the degree of histological inflammation and mucosal IL8 activity in patients with quiescent ulcerative colitis, and may predict the probability of subsequent disease relapse in patients with ulcerative colitis in remission.

Review article: what are the important endoscopic lesions for detection of dysplasia in inflammatory bowel disease?

It is recognized that inflammatory bowel diseases predispose to colorectal adenocarcinoma. Early detection of precursor lesions and subsequent treatment may prevent cancer development and this is possible with colonoscopy and biopsy. Inflammatory bowel disease-associated precursor lesions (dysplasia = intraepithelial neoplasia) must be distinguished from sporadic adenomas, occurring in non-colitic mucosa. Macroscopic lesions suspected of harbouring precursor lesions include irregular 'polypoid or elevated' lesions, which are usually broad-based and 'flat' lesions. Flat lesions are more common than elevated lesions and they are usually smaller. Chromoendoscopy increases the detection rate substantially as it allows targeted biopsies from suspicious lesions that increase the diagnostic yield of dysplasia. Ultimately, the combination of chromoendoscopy, or more advanced endoscopic techniques, and targeted biopsies may become the standard approach, rather than random biopsy sampling.

Reduction of miss rates of colonic adenomas by zoom chromoendoscopy

BACKGROUND AND AIMS

The aim of this study was to determine the detection rate of polyps using zoom chromoendoscopy (ZE) compared with standard video colonoscopy.

PATIENTS AND METHODS

End-to-end colonoscopies were performed in 50 patients by two different endoscopists blinded for each other's results. Lesions detected during initial standard colonoscopy (C1) were biopsied or removed by snare resection. The second colonoscopy (C2) was done with a zoom colonoscope spraying the whole colon with indigocarmine (0.4%). In addition, detected mucosal lesions were documented prior to ZE and then classified according to the pit pattern classification before biopsy or removal. The retrieval time for each procedure was determined.

RESULTS

The average retrieval time for C1 was 13+/-9 min (9-24) and 28+/-11 min (16-38, p<0.05) for ZE. During C1, 56 lesions were detected in 26 of 50 patients (34 hyperplastic and 22 adenomatous). During C2, 19 additional polyps were documented prior to ZE (15% tandem miss rate), and 20 further lesions were detected with ZE (21% additional polyp detection rate compared to C1 and C2 without ZE). Of the 39 additional lesions removed during C2 after ZE, 29 were hyperplastic and 10 were adenomatous. Most adenomas detected during the second investigation were found in patients in whom adenomatous polyps had already been removed during the initial colonoscopy (9 of 26 patients vs 1 of 24 patients, p<0.02). No carcinoma was detected. The pit pattern classification allowed a correct differentiation between hyperplastic and adenomatous polyps (accuracy 93%, sensitivity 90%, specificity 97%).

CONCLUSION

Using zoom chromoendoscopy, the rate of detecting colonic polyps can be increased at the cost of a longer retrieval time.

Primary signet-ring cell carcinoma of the colon at early stage: A case report and a review of the literature

A 67-year-old man, who had undergone surgery to resect multiple gastric cancers 4 years ago, visited our hospital for surveillance colonoscopy. Colonoscopy revealed a discolored, 7-mm in diameter, flat-elevated lesion with central depression in the transverse colon near the splenic flexure. Although the findings of endoscopy and barium enema were suggestive of submucosal invasion, the patient chose to undergo endoscopic mucosal resection. Pathological examination of the resected specimen revealed signet-ring cell carcinoma and a positive surgical margin. A second operation was performed, and no residual tumor or metastasis to lymph nodes was found in the resected specimens. Primary colorectal cancers composed of signet-ring cell carcinoma detected and treated at an early stage are extremely rare. We present a case and review the literature.

Assessment of rectal aberrant crypt foci by standard chromoscopy and its predictive value for colonic advanced neoplasms

BACKGROUND AND AIMS

Aberrant crypt foci (ACF) are thought to be preneoplastic lesions and are assessed by magnifying chromoscopy with methylene blue staining. The aim of this study was to evaluate the predictive value of rectal ACF recognized by conventional chromoscopy for colonic advanced neoplasms.

METHODS

Total colonoscopy, involving rectal chromoscopy using indigo carmine with standard colonoscopies, was performed on 386 patients. Patients who showed no ACF were classified as Grade 0, and those who had 1-4, 5-9, and 10+ ACF were classified as Grades 1, 2, or 3, respectively. The correlation between ACF grading and the prevalence of colonic advanced neoplasm, any adenoma>or=1 cm in size and/or with villous or tubulovillous morphology, and/or with high-grade dysplasia or invasive cancer, was assessed.

RESULTS

Sixty-three patients were classified as ACF Grade 0, 119 as Grade 1, 116 as Grade 2, and 88 as Grade 3. Colonic advanced neoplasm was observed in 4 patients (6.3%) for Grade 0, 43 (36.1%) for Grade 1, 61 (52.6%) for Grade 2, and 57 (64.8%) for Grade 3. As the ACF grade increased, the chance of a patient having a colonic advanced neoplasm increased. For multivariate analyses, compared with patients with Grade 0, those with Grades 1, 2, or 3 had a greater risk of colonic advanced neoplasm (odds ratio [OR] 9.18, 95% CI 3.08-27.33, OR 20.44, 95% CI 6.81-61.42, and OR 32.94, 95% CI 10.49-103.41, respectively).

CONCLUSIONS

Chromoscopic assessment of rectal ACF by conventional techniques is useful for predicting colonic advanced neoplasms.

Real-time in vivo virtual histology of colorectal lesions when using the endocytoscopy system

BACKGROUND

The histological findings of GI lesions are based on light-microscopic examination of H&E-stained thin-slice specimens. Recently, a concept of optical biopsy has been advocated. A study of the observation of colorectal lesions using endocytoscopy to obtain real-time histological images in vivo during endoscopy was performed.

DESIGN

Prospective study.

AIM

To evaluate the usefulness of optical biopsy of colorectal lesions with the endocytoscopy (E-C) system.

PATIENTS

The subjects were 113 consecutive patients who underwent a complete colonic examination, from April 2003 to March 2004, performed by a single colonoscopist.

SETTING

Digestive Disease Center of Showa University Northern Yokohama Hospital.

RESULTS

With E-C, it was possible to observe lesions at the cellular level and evaluate cellular atypia in addition to structural atypia in vivo. The correlation was statistically significant between the endocytoscopic diagnosis and the histological diagnosis.

LIMITATIONS

The endocytoscope had to be touched to the target colonic glands.

CONCLUSIONS

It was possible to distinguish neoplastic from non-neoplastic lesions, and also possible to distinguish invasive cancer from adenoma. "Ultra-high" magnifying endoscopy, the E-C system, provides real-time histological images in vivo, which correspond well with those of H&E-stained microscopic images.

Magnifying colonoscopy as a non-biopsy technique for differential diagnosis of non-neoplastic and neoplastic lesions

AIM: To clarify whether mucosal crypt patterns observed with magnifying colonoscopy are feasible to distinguish non-neoplastic polyps from neoplastic polyps.

METHODS: From June 1999 through March 2000, 180 consecutive patients with 210 lesions diagnosed with a magnifying colonoscope (CF-200Z, Olympus Optical Co., Ltd., Tokyo, Japan) were enrolled. Magnification and chromoendoscopy with 0.2% indigo-carmine dye was applied to each lesion for mucosal crypt observation. Lesions showing types I and II crypt patterns were considered non-neoplastic and examined histologically by biopsy, whereas lesions showing types III to V crypt patterns were removed endoscopically or surgically. The correlation of endoscopic diagnosis and histologic diagnosis was then investigated.

RESULTS: At endoscopy, 24 lesions showed a type I or II pit pattern, and 186 lesions showed type III to V pit patterns. With histologic examination, 26 lesions were diagnosed as non-neoplastic polyps, and 184 lesions were diagnosed as neoplastic polyps. The overall diagnostic accuracy was 99.1% (208/210). The sensitivity and specificity were 92.3% (24/26) and 99.8% (184/186), respectively.

CONCLUSION: Magnifying colonoscopy could be used as a non-biopsy technique for differentiating neoplastic and non-neoplastic polyps.

Early colorectal cancer: concept, diagnosis, and management

In colorectal cancers, although flat and depressed-type lesions are found by regular endoscopic view, magnification and pit-pattern observation are vital parts of the precise diagnosis of the lesion. The depressed-type lesions appear to have a prominent tendency to show malignant characteristics, and the recognition and timely treatment of such lesions is important for improving the morbidity and mortality of colorectal cancer. Chromoscopy is mandatory for an accurate diagnosis of these lesions. The pit-pattern classification correlates well with actual histological findings and can provide important additional information prior to endoscopic treatment of the lesion.

Flat and depressed lesions of the colorectum

Although flat and depressed-type lesions are found by regular endoscopic view, magnification and pit pattern observation are vital parts of a precise diagnosis of the lesion. The depressed-type lesions have a prominent tendency to show malignant character, and the recognition and timely treatment of this lesion is inevitable in improving the morbidity and mortality from colorectal cancer. A magnifying colonoscope has the capability of a regular colonoscope with an additional feature: magnification. With chromoscopic techniques, the surface pattern of the mucosal pits can be observed. The pit-pattern classification correlates well with actual histologic findings and provides important additional information before endoscopic treatment of the lesion.

The clinical meaning of a nonstructural pattern in early gastric cancer on magnifying endoscopy

BACKGROUND

In the field of colorectal cancer, the presence of a nonstructural pattern in magnifying colonoscopy means that cancer involves the submucosal layer. Since en bloc EMR was developed, differentiation between mucosal and submucosal cancer is a critical issue in the management of gastric cancer. In this study, we evaluated the clinical meaning of a nonstructural pattern in magnifying gastroscopy.

METHODS

Between April 2002 and July 2003, 59 patients with 50 cancers and 11 adenomas were enrolled in this study. A cancerous lesion was subclassified into a differentiated-type group or a undifferentiated-type group according to histologic type. Before treatment, magnifying endoscopic observation was performed. After EMR or surgical intervention, resected specimens were observed by using stereomicroscopy. In both in vivo magnifying endoscopic and in vitro stereomicroscopic observations, the presence of a nonstructural pattern on the lesion was investigated. Compared with histologic findings, the clinical meaning of the presence of a nonstructural pattern on the gastric neoplastic lesion was evaluated.

RESULTS

A nonstructural pattern could not be confirmed in any adenomas and in 29 of 31 mucosal differentiated cancers. However, in 9 of 11 submucosal cancers, a nonstructural pattern could be identified.

CONCLUSIONS

The presence of a nonstructural pattern appeared to be a useful marker to not proceed with EMR of gastric cancer.

In vivo imaging of colitis and colon cancer development in mice using high resolution chromoendoscopy

BACKGROUND

Mouse models of colitis and cancer are indispensable for our understanding of the pathogenesis of these diseases. In the past, mice had to be sacrificed in order to analyse colitis activity and tumour development. We have developed a safe method for high resolution endoscopic monitoring of living mice.

METHODS

Mice developing colitis or colonic tumours were anaesthetised using avertine and repeatedly examined by endoscopy. A novel miniendoscope (1.9 mm outer diameter), denoted Coloview, was introduced via the anus and the colon was carefully insufflated with an air pump before analysis of the colonic mucosa. An extra working channel allowed the introduction of biopsy forceps or injection needles as well as surface staining with methylene blue in order to visualise the surface of the crypts and the pit pattern architecture.

RESULTS

Endoscopic pictures obtained were of high quality and allowed monitoring and grading of disease. Scoring of colitis activity as well as tumour size and growth was possible. In addition, pit pattern analysis using chromoendoscopy permitted discrimination between inflammatory and neoplastic changes. Biopsies yielded enough tissue for molecular and histopathological analyses.

CONCLUSIONS

In summary, chromoendoscopy in mice allows monitoring of the development of colitis and colon cancer with high resolution. Manipulations such as local injection of reagents or taking biopsies can be performed easily.

Frequency and spectrum of K-RAS codons 12 and 13 mutations in colorectal adenocarcinomas from Taiwan

Mutations in codons 12 and 13 of the K-RAS oncogene are detected at a remarkably high frequency in colorectal adenocarcinoma and are believed to be a critical event in oncogenesis. In the present study, we evaluated colorectal tumor specimens from Taiwan for mutations in K-RAS codons 12 and 13 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and direct DNA sequencing. Mutations were found in 48 of 181 (26.5%) tumors, 30 mutations were G-->A transitions (62.5% of all mutations), 14 were G-->T transversions (29.2%), and only 4 were G-->C transversions (8.3%). Similar relative mutation frequencies and spectra were found regardless of the sex of the patient, the tumor grade, or the tumor stage. The high frequency of transitions among K-RAS mutation suggests that G/T mismatches play an important role in the oncogenesis of colorectal adenocarcinoma, implying that alkylating carcinogens may be involved in the colorectal carcinogenesis. Although the frequency of mutation (26.5%) appears to be lower than those reported in the United States (40%), France (49%), and the Netherlands (34%), the spectrum of point mutations in codons 12 and 13 of the K-RAS gene in the Taiwan Chinese population appears to be similar. The reason for these results may be that diet and ethnicity are not rate limit factors in controlling the spectra of mutations but influence on the frequency of K-RAS mutations in human colorectal adenocarcinomas.

Efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions

Magnifying chromoendoscopy is an exciting new tool and offers detailed analysis of the morphological architecture of mucosal crypt orifices. In this review, we principally show the efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions such as prediction between non‐neoplastic lesions and neoplastic ones, and distinction between endoscopically treatable early invasive cancers and untreatable cancers based on a review of the literature and our experience at two National Cancer Centers in Japan. Overall diagnostic accuracy by conventional view, chromoendoscopy and chromoendoscopy with magnification ranged from 68% to 83%, 82% to 92%, and 80% to 96%, respectively, and diagnostic accuracy of accessing the stage of early colorectal cancer using magnifying colonoscopy was over 85%. Although the reliability depends on the skill in magnifying observation, widespread applications of the magnification technique could influence the indications for biopsy sampling during colonoscopy and the indication for mucosectomy. Moreover, the new detailed images seen with magnifying chromoendoscopy are the beginning of a new period in which new optical developments, such as narrow band imaging system, endocytoscopy system, and laser‐scanning confocal microscopy, will allow a unique look at glandular and cellular structures.

Crystal violet chromoendoscopy with mucosal pit pattern diagnosis is useful for surveillance of short-segment Barrett's esophagus

BACKGROUND

Because of a rapid increase in the incidence of Barrett's cancer, the appropriate surveillance method for Barrett's esophagus is of interest. Methylene blue chromoendoscopy has been reported to be an effective and inexpensive method to improve biopsy surveillance of Barrett's epithelium. However, the usefulness of this method in short-segment Barrett's esophagus cases is still controversial.

AIMS

This study was undertaken to evaluate the abilities of crystal violet and methylene blue chromoendoscopy to detect potentially dysplastic Barrett's epithelium in cases with short-segment columnar-appearing epithelium of the esophago-gastric junction.

PATIENTS AND METHODS

Four hundred patients with endoscopically suspected short-segment Barrett's esophagus were enrolled and randomly assigned to receive chromoendoscopy with 0.05% crystal violet, 0.1% crystal violet, 0.5% methylene blue, or 1.0% methylene blue. During crystal violet and methylene blue chromoendoscopy, biopsy specimens were obtained from stained and unstained columnar-appearing epithelium of the esophago-gastric junction, and the detection rates of Barrett's epithelium were evaluated. The value of pit pattern diagnosis was also evaluated as a possible way to detect dysplastic Barrett's epithelium.

RESULTS

Chromoendoscopy with 0.05% crystal violet detected histologically confirmed Barrett's epithelium with the highest sensitivity (89.2%) and specificity (85.7%). Crystal violet clearly stained both dysplastic and nondysplastic Barrett's epithelia and made the surface pit pattern easy to observe without using magnifying endoscopy.

CONCLUSIONS

The combination of crystal violet chromoendoscopy and pit pattern diagnosis is considered to be useful for the surveillance of short-segment Barrett's esophagus.

Dye spraying and magnifying endoscopy for dysplasia and cancer surveillance in ulcerative colitis

PURPOSE

The aim of this study was to investigate detection of dysplasia or colitic cancer with ulcerative colitis by use of magnifying endoscopic observation.

METHODS

From 1986 through 2000, ulcerative colitis was diagnosed and treated in 886 patients at Kitasato University East Hospital. Of the total, we studied 25 patients in depth: 14 who had dysplasia alone, 5 in whom cancer was diagnosed during follow-up after the detection of dysplasia, and 6 who had colitic cancer.

RESULTS

Dysplasia was detected in 11 (3.2 percent) of 345 patients with extensive colitis and in 8 (3.7 percent) of 217 with left-sided colitis. Colorectal cancer was diagnosed in nine patients (2.6 percent) with extensive colitis and in two (0.9 percent) with left-sided colitis. Neither dysplasia nor colitic cancer was found in patients with proctitis-type colitis. Endoscopically, dysplasia and early cancer were characterized by granular or nodular protruding mucosa or by lowly protruding or flat mucosa, often associated with redness. Dye-spraying endoscopy was useful for detection. Magnifying endoscopy of ten regions of dysplasia (7 patients) and five early cancers (4 patients) showed IIIS to IIIL type pits or IV type pits. Biopsy of sites showing tumorous pits on magnifying endoscopy revealed dysplasia and early cancer. Observation of the pit pattern was found to be diagnostically useful.

CONCLUSIONS

Dye spraying and magnifying endoscopy are useful for the detection, targeted biopsy, and diagnosis of dysplasia and colitic cancer in patients with ulcerative colitis.

Interobserver and intra-observer consistency in the endoscopic assessment of colonic pit patterns

BACKGROUND

The colonic pit pattern is recognized as an aid to the differential diagnosis between hyperplastic lesions, adenoma, and carcinoma, and is a focus for observation by magnification chromoendoscopy, especially in Japan. This study evaluated intra- and interobserver agreement of experienced endoscopists in the assessment of colonic pit patterns when using the Kudo classification.

METHODS

A total of 220 magnification chromoendoscopic pictures of colonic lesions were selected, of which 215 were collected from a consecutive series of patients. The pictures were randomly displayed twice to 6 experienced endoscopists at an interval of 1 week. Each picture was assessed for predominant pit pattern by using the classification of Kudo. Histopathologic diagnosis also was predicted based on the pit pattern diagnosis. Kappa statistics were used to estimate intra- and interobserver variation.

RESULTS

The mean (standard deviation) inter- and intra-observer kappa values for experienced endoscopists were 0.716 (0.031) and 0.810 (0.084), respectively. For prediction of histopathology according to the pit pattern diagnosis, the mean (standard deviation) inter- and intra-observer kappa values were 0.776 (0.032) (p = 0.001) and 0.862 (0.069) (p = 0.028), respectively.

CONCLUSIONS

For experienced endoscopists, the inter- and intra-observer reproducibility of the classification of colonic pit pattern is good.

Magnifying endoscopy with indigo carmine contrast for differential diagnosis of neoplastic and nonneoplastic colonic polyps

This study describes the feasibility of magnifying colonoscopy with indigo carmine dye contrast to distinguish neoplastic and nonneoplastic colonic polyps. This study sampled consecutive patients undergoing colonoscopy using an Olympus CF240ZI from January to October 2000 at Chang-Gung Memorial Hospital, Lin-Kou Medical Center. This study analyzed a total of 270 polyps. Indigo carmine (0.2%) was sprayed directly on the mucosa surface before observing the crypts using a magnifying colonoscope (1.5x-100x). The pit patterns were described using the classification proposed by Kudo. Finally, polypectomy or biopsy was performed for histological diagnosis. The study identified 155 adenomas, 99 hyperplastic polyps, 9 adenocarcinomas, and 7 other nonneoplastic lesions (harmatoma, inflammatory polyps, and mucosal tag). The pit pattern was analyzed for all lesions. Further classification into neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic and others) polyps revealed 156 neoplastic and 14 nonneoplastic polyps among the type III to type V pits and 92 nonneoplastic and 8 neoplastic polyps among the type I and II pits. The sensitivity of type III to type V pits in detecting neoplastic polyps was 95.1%, with a specificity of 86.8% and diagnostic accuracy of 91.9%. The positive likelihood ratio was 7.3, and the negative likelihood ratio was 0.06. Magnifying colonoscopy with indigo carmine dye contrast provides morphological detail that correlates well with polyp histology. Small flat lesions with typical type II pit pattern should have minimal neoplastic risk, thus endoscopic resection is not necessary.

Chromoendoscopy of the colon

Chromoendoscopy is a technique that uses tissue stains to better characterize, delineate, or highlight the gastrointestinal mucosa. Chromoendoscopy of the colon has the potential to significantly aid the endoscopist in the recognition and identification of mucosal abnormalities ranging from inflammation to neoplasia.

Appearance of enhanced tissue features in narrow-band endoscopic imaging

This study was performed to examine the usefulness of medical endoscopic imaging utilizing narrow-band illumination. The contrast between the vascular pattern and the adjacent mucosa of the underside of the human tongue was measured using five narrow-band illuminations and three broadband illuminations. The results demonstrate that the pathological features of a vascular pattern are dependent on the center wavelength and the bandwidth of illumination. By utilizing narrow-band illumination of 415+/-30 nm, the contrast of the capillary pattern in the superficial layer was markedly improved. This is an important benefit that is difficult to obtain with ordinary broadband illumination. The appearances of capillary patterns on color images were evaluated for three sets of filters. The narrow, band imaging (NBI) filter set (415+/-30 nm, 445+/-30 nm, 500+/-30 nm) was selected to achieve the preferred appearance of the vascular patterns for clinical tests. The results of clinical tests in colonoscopy and esophagoscopy indicated that NBI will be useful as a supporting method for observation of the endoscopic findings of early cancer.

Relationship between matrix metalloproteinase-7 and pit pattern in early stage colorectal cancer

BACKGROUND

The surface pit pattern of early stage colorectal cancer changes with tumor growth and invasion. It was postulated by us that the expression of matrix metalloproteinase-7 is related to tumor invasiveness and disturbance of the pit pattern.

METHODS

Sixty-eight colorectal epithelial tumors were examined, and the pit pattern was classified by stereoscopic microscopy. Immunostaining for matrix metalloproteinase-7 and its substrate laminin were performed.

RESULTS

The rate of matrix metalloproteinase-7 positive staining was significantly higher for mucosal (70.6%) and submucosal cancer (80.0%) than for adenoma (18.6%) (p<0.0083). The rate of matrix metalloproteinase-7 positive specimens was significantly higher for type IV and type V compared with type III pit patterns. Where the tumor surface was positive for matrix metalloproteinase-7, expression of laminin was negative in 40% of specimens with a type IV pit pattern and 100% of those with the type V pit pattern.

CONCLUSIONS

The results of this study indicate that expression of matrix metalloproteinase-7 is related to both the invasiveness of colorectal epithelial tumors and the disturbance of the pit pattern on the tumor surface.

Two cases of inverted hyperplastic polyps of the colon and association with adenoma

Here we report two cases of inverted hyperplastic polyps of the colon. The first patient showed three inverted hyperplastic polyps in the ascending colon, one of which was associated with adenoma. We immunostained this adenoma-associated polyp using anti-beta-catenin antibody and found accumulation of beta-catenin in the cytoplasm of the adenomatous lesion but not in the inverted hyperplastic polyp. This suggested an adenomatous polyposis coli (APC) mutation in the adenomatous region but not in the inverted hyperplastic polyp. The inverted hyperplastic polyp in the second patient was located at the caecum and was studied using magnifying colonoscopy. The polyp appeared to be flat and elevated with a depressed pit in the centre. After spraying with methylene blue dye, the pit pattern of the lesion was observed and small asteroid pits on the polyp were found, consistent with a hyperplastic gland pattern. From these results, we diagnosed inverted hyperplastic polyp of the colon by colonoscopy.

Magnification endoscopy, high resolution endoscopy, and chromoscopy; towards a better optical diagnosis

In the past few years, optical magnification endoscopy and chromoscopy have gained renewed interest in the West as a means for the early detection of minute lesions in patients with Barrett's oesophagus and in patients referred for colonic cancer screening. In Barrett's oesophagus, the vast majority of data on the use of chromoscopy deals with the application of methylene blue. Conventional videoendoscopy in combination with methylene blue staining improves the detection of Barrett's mucosa. A correlation has been shown between variation and intensity of staining and histologically verified stages of dysplasia or cancer. Magnification endoscopy and chromoscopy improve the detection of colonic non-polypoid lesions associated with neoplasia and carcinoma. Pitt pattern analysis enables the distinction of non-neoplastic non-polypoid lesions (type I and II) from neoplastic type non-polypoid lesions (type III-V) with great accuracy. It is certain that "old fashioned" chromoscopy combined with advanced endoscopic technology carry a great diagnostic potential and should be further put to the test for use in daily clinical practice.

A comparison of magnifying and nonmagnifying colonoscopy for diagnosis of colorectal polyps: A prospective study

BACKGROUND

Discrimination between neoplastic and non-neoplastic colorectal polyps is essential for determining appropriate treatment. The mucosal crypt pattern of polyps can be observed with a nonmagnifying colonoscope; however, mucosal crypt patterns are better seen by magnifying colonoscopy, which can also be a noninvasive means for predicting histopathology. This study prospectively compared the ability to distinguish between neoplastic and non-neoplastic lesions by magnifying and nonmagnifying colonoscopy.

METHODS

Six hundred sixty patients were randomly assigned to undergo magnifying or nonmagnifying colonoscopy (2 groups each of 330 patients). The mucosal crypt pattern of colorectal lesions was classified into types I through V after spraying with 0.2% Indigo carmine dye. The histopathology of all lesions was confirmed by evaluation of endoscopic resection specimens or biopsy specimens. Only lesions 10 mm or less in diameter were included in the study.

RESULTS

The accuracy of magnifying colonoscopy in distinguishing neoplastic from non-neoplastic lesions (92%, 372/405) was significantly higher than for nonmagnifying colonoscopy (68%, 278/407). Insertion of magnifying and nonmagnifying colonoscopes to the cecum was successful in, respectively, 321 patients (97%) and 317 patients (96%), with no significant differences in the average time to reach the cecum or average total procedure time. No serious complication was observed during or immediately after the examinations.

CONCLUSIONS

Observation of mucosal crypt pattern with magnifying colonoscopy is superior to nonmagnifying colonoscopy for distinguishing between neoplastic and non-neoplastic colorectal lesions.

Minute findings by magnifying colonoscopy are useful for the evaluation of ulcerative colitis

BACKGROUND

Colonoscopy has an important role in the diagnosis of ulcerative colitis. However, colonoscopic findings are inadequate for the prediction of relapse without histologic examination. In this study, the role of magnifying colonoscopy in ulcerative colitis was evaluated.

METHODS

One hundred sixteen magnifying colonoscopy observations were made in 61 patients with ulcerative colitis between January 1994 and October 1998. A simple classification of magnifying colonoscopic findings into 5 categories was devised as follows: regularly arranged crypt openings, villous-like, minute defects of epithelium, small yellowish spots, and coral reef-like appearance. The colonoscopic findings by classification were compared with histopathologic findings, and the usefulness of the classification for predicting relapse was prospectively analyzed in 18 patients.

RESULTS

Compared with grade as determined by conventional colonoscopy, there was a better correlation between the classification of findings by magnifying colonoscopy and histopathologic findings (r(2) = 0.665, 0.807, respectively). Of 18 patients studied prospectively, 7 of 9 with minute defects of epithelium relapsed within 6 months, and the cumulative nonrelapsing rate was significantly lower in patients with minute defects of epithelium compared with those without minute defects of epithelium (p = 0.0059). Moreover, minute defects of epithelium was found to be a significant independent predictive factor for relapse (multivariate analysis, Cox proportional hazards model; p = 0.0203).

CONCLUSIONS

Our proposed classification of magnifying colonoscopic findings in patients with ulcerative colitis is useful for the evaluation of disease activity and for the prediction of periods of remission.

Subepithelial vascular patterns in bronchial dysplasias using a high magnification bronchovideoscope

BACKGROUND

We have developed a method of high magnification bronchovideoscopy that enables improved observation of subepithelial vascular patterns of the bronchial mucosa. A study was undertaken to investigate the value of high magnification bronchovideoscopy in the detailed examination of dysplasia in the bronchial mucosa of patients with abnormal mucosal fluorescence.

METHODS

Thirty one patients with sputum cytology specimens suspicious or positive for malignancy were entered into the study. Conventional white light examination was first performed under local anaesthesia and fluorescence bronchoscopy was also carried out using a light induced fluorescence endoscopy (LIFE) lung system. A high magnification bronchovideoscope (XBF 200HM2) was then used to examine the microvascular network in the bronchial mucosa at sites of normal and abnormal fluorescence and the images obtained were compared with pathological diagnoses from bronchial biopsy specimens. Vascular area ratios were calculated using image analysing apparatus.

RESULTS

Vascular networks with regular patterns were observed at 20 of 22 abnormal fluorescence sites in biopsy specimens from patients with bronchitis. However, vascular networks with increased vessel growth and complex networks of tortuous vessels of various sizes were observed in 15 of 21 abnormal fluorescence sites in dysplasia specimens. There was a significant difference between bronchitis and dysplasia specimens (OR=25, 95% CI 5.5 to 113, p<0.0001). Mean vascular area ratios from 16 normal bronchial epithelium specimens with normal fluorescence, and 22 bronchitis and 21 dysplasia specimens with abnormal fluorescence were 0.054 (95% CI 0.039 to 0.07), 0.095 (95% CI 0.072 to 0.118), and 0.173 (95% CI 0.143 to 0.203), respectively. The results indicate a statistically significant increase in vascular area in the three groups (p<0.0001).

CONCLUSION

Areas of increased vessel growth and complex networks of tortuous vessels in the bronchial mucosa detected using a high magnification bronchovideoscope at sites of abnormal fluorescence may enable discrimination between bronchitis and dysplasia.

Comparison of EUS and magnifying colonoscopy for assessment of small colorectal cancers

BACKGROUND

Prediction of invasion depth and lymph node metastasis is mandatory when local treatment is considered for small colorectal cancer. The aim of this study was to compare the accuracy of EUS with a catheter probe (probe-EUS) and magnifying colonoscopy for prediction of invasion depth and lymph node metastasis for small colorectal cancer.

METHODS

Small colorectal cancers were imaged by both probe-EUS and magnifying colonoscopy. Invasion depth by probe-EUS was determined by the presence or absence of distortion of the third sonographic layer. Findings by magnifying colonoscopy were divided into regular, distorted, and amorphous patterns. Histopathologically, depth of invasion was classified as intramucosa/slight or deep invasion. Findings by probe-EUS and magnifying colonoscopy were compared with respect to deep invasion and lymph node metastasis.

RESULTS

There were 22 small colorectal cancers with intramucosa/slight invasion and 28 with deep invasion. Four of 30 cancers had associated lymph node metastasis. Accuracy for depth of invasion was 91.8% for probe-EUS and 63.3% in magnifying colonoscopy, the difference being statistically significant (p = 0.0013). Negative predictive value of probe-EUS for deep invasion was higher than that for magnifying colonoscopy (respectively, 90.9% vs. 54.1%) in the population studied (prevalence deep invasion 56%). The accuracy for lymph node metastasis was 24.1% for probe-EUS and 72.4% for magnifying colonoscopy, the difference being statistically significant (p < 0.001). Positive predictive value for lymph node metastasis was higher when the amorphous pattern was noted by magnifying colonoscopy compared with the positive predictive value for deep invasion by probe-EUS (respectively, 33.3% vs. 8.7%) in the population studied (prevalence lymph node metastasis 13.3%).

CONCLUSIONS

Probe-EUS is superior to magnifying colonoscopy for determination of invasion depth in small colorectal cancer. Magnifying colonoscopy may be predictive of lymph node metastasis, thereby suggesting that the procedures provide complementary information with respect to the decision for local versus surgical therapy.

[Colonic polyps diagnosis by conventional video colonoscopes and chromoscopy with indigo carmine dye solution]

BACKGROUND

Magnification colonoscopy and contrast chromoscopy with indigo carmine dye solution have been used to differentiate neoplastic polyps (adenomas and adenocarcinomas) from non-neoplastic (hyperplastic, inflammatory, juvenile) in an attempt to obviate endoscopic polypectomy. On the other hand, little published information exists concerning conventional video colonoscopes and chromoscopy for polyp histology prediction. Aim - To assess usefullness of conventional video colonoscopes and contrast chromoscopy with indigo carmine solution for differential diagnosis of colon polyps.

METHODS

In a routine colonoscopy series, we performed chromoscopy with conventional video colonoscopes before endoscopic excision of detected polyps. If a sulcus pattern was observed on the surface of the lesion, it was classified as neoplastic. Polyps were classified as non-neoplastic if no sulcus was detected on its surface. These observations were then compared with histology.

RESULTS

In the study period (18 months), we detected 133 polyps in 53 patients. We were able to compare results of histology and chromoscopy in 126 lesions. The sensitivity, specificity, diagnostic accuracy, negative predictive value, and positive predictive value were 56,4%, 79,2%, 65,1%, 52,8%, and 81,5%, respectively.

CONCLUSION

On the base of the presented data, we concluded that conventional video colonoscopes and contrast chromoscopy with indigo carmine solution is not a good technique for differential diagnosis of colon polyps.

Differential distribution of basement membrane type IV collagen alpha1(IV), alpha2(IV), alpha5(IV) and alpha6(IV) chains in colorectal epithelial tumors

In this study, we examined the relationship between the histopathological grade and immunohistochemical localization of six genetically distinct type IV collagen alpha chains, the major component of basement membrane (BM), in normal and neoplastic colorectal tissues. In the normal colorectal mucosa, alpha1/alpha2(IV) and alpha5/alpha6(IV) chains were stained in all epithelial BM. However, alpha3/alpha4(IV) chains were restrictively immunostained in the BM of the apical surface epithelium. Similar immunostaining profiles for alpha1/alpha2(IV) and alpha5/alpha6(IV) chains were observed in tubular adenomas with mild/moderate atypia. However, in intramucosal carcinomas, both alpha1/alpha2(IV) chains were linearly stained in the BM of cancer cell nests, while the assembly of alpha5/alpha6(IV) chains into the BM was inhibited in a discontinuous or negatively stained pattern. The normal colorectal mucosa forms a second network of BM composed of alpha5/alpha6(IV), partly alpha3/alpha4(IV) chains, in addition to the classic network of alpha1/alpha2(IV) chains. The differential immunohistochemical localization of the type IV collagen alpha5/alpha6 chains could be one diagnostic marker for the invasiveness of colorectal cancer.

Early detection of colorectal cancer using high-magnification chromoscopic colonoscopy

BACKGROUND

Endoscopic techniques aimed at early detection of colorectal cancer (CRC) and its precursors, permitting targeted in vivo luminal treatments, have been developed by the Japanese since the early 1990s. The introduction of this new technology to the UK (i.e. magnification endoscopes) may permit earlier and more accurate diagnosis. According to Japanese data, magnification chromoscopy can be used to predict histology and invasive depth of cancer, and help in the detection of flat and depressed colonic lesions. Flat and depressed lesions are not purely Japanese phenomena: they exist with a similar incidence in the UK.

METHODS

A Medline search was performed for the years 1955-2001 using the following medical subject headings and search methodology: colorectal cancer and colonoscopy or aberrant crypt foci or molecular kinetics or flat/depressed lesions or chromoscopy.

RESULTS AND CONCLUSION

Early CRC, in the form of flat or depressed lesions, can be difficult to detect using conventional colonoscopic techniques and penetrate the colonic mucosa deeply. The implications of detecting these lesions in relation to current approaches to the prevention of CRC are profound.