Stereomicroscopic examination of surface morphology in colorectal epithelial tumors

A comparison of magnifying chromoendoscopy versus histopathology of forceps biopsy specimen in the diagnosis of minute flat adenoma of the colon

Having noted a discrepancy between endoscopic and histopathological diagnoses in cases of minute adenomas of the colon, a prospective study was designed to clarify which is appropriate, magnifying chromoendoscopy or histopathology of a specimen obtained by biopsy forceps. A total of 208 patients comprised the study population. The endoscopic diagnoses were performed with magnifying colonoscopies. We separated the detected lesions with type III(L) pit pattern following Kudo's classification into two groups at random: in group A (n = 104) resected specimens were fixed with 20% buffered formalin without being flattened, whereas in group B (n = 104) the resected specimens were flattened using forceps before fixation and the specimens were cut under observation of their surface structure with stereomicroscopy. Comparison of the initial diagnoses between groups A and B showed that a total of 84.6% (88/104) of the lesions were diagnosed to be tubular adenomas histopathologically in group A, compared with 100% (104/104) in group B (P < 0.0001). Results for comparison of the secondary diagnoses between group A and group B showed that 14 of the 16 lesions were diagnosed as tubular adenomas histopathologically. Thereafter, 98.1% (102/104) of the lesions were diagnosed to be tubular adenomas histopathologically in group A (P = 0.4976). In conclusion, high-resolution magnifying chromoendoscopy is an appropriate procedure for the diagnosis of minute adenomas in comparison with histopathology of specimens obtained by biopsy forceps in this prospective study.

Automated quantification of colonic crypt morphology using integrated microscopy and optical coherence tomography

Colonic crypt morphological patterns have shown a close correlation with histopathological diagnosis. Imaging technologies such as high-magnification chromoendoscopy and endoscopic optical coherence tomography (OCT) are capable of visualizing crypt morphology in vivo. We have imaged colonic tissue in vitro to simulate high-magnification chromoendoscopy and endoscopic OCT and demonstrate quantification of morphological features of colonic crypts using automated image analysis. 2-D microscopic images with methylene blue staining and correlated 3-D OCT volumes were segmented using marker-based watershed segmentation. 2-D and 3-D crypt morphological features were quantified. The accuracy of segmentation was validated, and measured features are in agreement with known crypt morphology. This work can enable studies to determine the clinical utility of high-magnification chromoendoscopy and endoscopic OCT, as well as studies to evaluate crypt morphology as a biomarker for colonic disease progression.

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.

Accuracy of radiographic assessment for the diagnosis of invasion depth in small invasive colorectal cancer

Radiographic findings of 113 submucosally invasive colorectal cancers (CRCs) <or=20 mm were investigated by two observers to examine whether barium radiography is predictive of the invasion depth in small colorectal cancer. Smooth surface, central barium fleck, fold convergency and eccentric rigidity were chosen as the radiographic determinants. Predictive values of the determinants for deep submucosal invasion were compared between 45 CRCs <or=10 mm and 68 CRCs >10 mm. 47 CRCs had invaded the submucosa superficially while 66 CRCs had invaded deeply. The concordance rate in the assessment of radiology was 90.3% in smooth surface, 92.9% in central barium fleck, 90.3% in fold convergency and 79.6% in eccentric rigidity. Positive predictive value of central barium fleck for deep submucosal invasion was significantly higher in CRCs>10 mm than in those <or=10 mm (0.86 vs. 0.64, p=0.034). In contrast, negative predictive values of smooth surface (0.89 vs. 0.34, p<0.00001), central barium fleck (0.87 vs. 0.38, p=0.0002), fold convergency (0.64 vs. 0.33, p=0.0023) and eccentric rigidity (0.79 vs. 0.48, p=0.023) were significantly higher in CRCs <or=10 mm than in those >10 mm. These findings suggest that barium radiography is a procedure which can give useful information in prediction of invasion depth in CRCs <or=10 mm in size.

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.

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.

Genetic pathways in colorectal and other cancers

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Genetic pathways in colorectal and other cancers

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Differences in the diagnostic criteria used by Japanese and Western pathologists to diagnose colorectal carcinoma

BACKGROUND

In view of the many studies of early stage colorectal carcinoma from Japan, it is essential to know whether the criteria for the histologic diagnosis of colorectal carcinoma are similar in Japan and Western countries.

METHODS

Eight expert pathologists from Japan (4), North America (2), and Europe (2) individually reviewed microscope slides of 20 colorectal lesions from Japanese patients who had undergone endoscopic mucosal resection or surgery because early stage carcinoma and/or adenoma was suspected. The pathologists indicated the pathologic findings on which they based each diagnosis.

RESULTS

For 11 slides that showed adenoma according to the Western pathologists with low grade dysplasia according to at least half of them, the Japanese diagnosed definite carcinoma with or without adenoma in 4 cases and adenoma in 5, and in 2 cases they were equally divided between a diagnosis of adenoma and carcinoma. For five slides showing adenoma with high grade dysplasia according to the Western pathologists, the Japanese diagnosed definite carcinoma with adenoma in three cases and adenoma in one, and in one case they were equally divided between a diagnosis of adenoma and carcinoma. For one case in which the Western pathologists were equally divided between a diagnosis of carcinoma and adenoma with high grade dysplasia, all the Japanese pathologists diagnosed definite carcinoma with or without adenoma. Three slides showed definite carcinoma with or without adenoma, according to both the Western and the Japanese pathologists. The presence of invasion was the most important diagnostic criterion of colorectal carcinoma for the Western pathologists, whereas for the Japanese the nuclear features and glandular structures were more important.

CONCLUSIONS

In Japan, colorectal carcinoma is diagnosed on the basis of nuclear and structural criteria, even in cases considered by Western pathologists to be noninvasive lesions with low grade dysplasia. This diagnostic practice may contribute to the relatively high incidence of early stage colorectal carcinoma reported in Japan as compared with Western countries.

Application of magnifying chromoscopy for the assessment of severity in patients with mild to moderate ulcerative colitis

BACKGROUND

A magnifying colonoscope that enables high-power observation of the colorectal mucosa has been recently developed. The aim of this study was to investigate the value of the magnifying instrument in determining the severity of ulcerative colitis.

METHODS

Magnifying colonoscopy was performed in 41 patients with ulcerative colitis, and the findings in the rectum were graded according to network pattern and cryptal openings. These findings were correlated with endoscopic, clinical, and histologic severity of the disease.

RESULTS

Magnifying colonoscopy did not detect network pattern in 37% and cryptal opening in 24% of the subjects. The clinical, endoscopic, and histologic grades of activity were not different between groups divided by the presence or absence of each finding. However, when the two features were coupled, patients with visible network pattern and cryptal opening had a lower clinical activity index and lower grade of histologic inflammation than those in whom both findings could not be visualized.

CONCLUSIONS

Observation under magnifying colonoscopy can be another clue to determining the severity of disease in patients with ulcerative colitis.

Macroscopic and stereomicroscopic diagnosis of superficial flat-type early carcinomas of the gallbladder

Superficial flat early carcinomas of the gallbladder are rarely detected clinically. We previously reported that these carcinomas display granular, flat, or gastric area-like surface mucosal patterns. However, these patterns are also seen in some non-neoplastic conditions. To more definitively differentiate carcinomas from non-neoplastic lesions, we analyzed the stereomicroscopic structure of macroscopically granular, flat, or gastric area-like mucosal lesions with a methylene-blue contrast technique. Sixteen superficial flat early carcinomas and 65 non-neoplastic flat lesions from surgically resected gallbladders were studied by stereomicroscopy. The fine mucosal structures were classified into three patterns: grooved, pitted, or papillary, each of which was further subdivided into regular and irregular. The frequency of the grooved (52.2%) and papillary (52.2%) patterns was significantly higher in the carcinomas than in the non-neoplastic lesions (24.7% and 1.3%, respectively). The pitted pattern was present in 69.6% of the carcinomas and in 53.2% of the non-neoplastic lesions (the difference was not significant). In the grooved and pitted patterns, the irregular subtypes predominated in the carcinomas (100% and 81.3%, respectively), while the regular subtypes were more frequent in the non-neoplastic lesions (84.2% and 97.6%, respectively). Stereomicroscopic examination of the fine mucosal structures of flat lesions of the gallbladder is very useful in differentiating carcinomas from non-neoplastic lesions.

Nonpolypoid adenomas and adenocarcinomas found in background mucosa of surgically resected colons

BACKGROUND

Nonpolypoid (depressed or flat) neoplasias are rarely seen in the colon and rectum. We previously reported their histogenesis and characteristics in patients with familial adenomatous polyposis (FAP), but their development in patients without FAP has not been studied systematically.

METHODS

Three hundred specimens of large intestinal mucosa surgically resected from patients with cancers or other diseases, excluding FAP, were examined with a dissecting microscope. The morphologic types, sizes, locations, and frequencies of detectable colorectal neoplasias, and their histologic features, were analyzed.

RESULTS

A total of 297 adenomas (240 polypoid, 32 flat, and 25 depressed type) were obtained. Nonpolypoid adenomas were most frequently found in the transverse and descending colon. Almost all depressed adenomas (24 of 25; 96%) were less than 3 mm in greatest dimension and almost all flat adenomas (31 of 32; 96.9%) were less than 3.5 mm in greatest dimension. Three minute, nonpolypoid adenocarcinomas (mean size, 2.6 mm; range, 2.4-2.9 mm) were also detected, two of them already invaded the submucosal layer.

CONCLUSIONS

Minute nonpolypoid type adenomas may be present in the background mucosa of patients without FAP. This study suggests that even minute nonpolypoid adenocarcinomas have an increased potential for endophytic growth.