[Clinicopathological features of the colorectal serrated adenoma and analysis on influencing factors of malignancy]

Objective: Serrated adenoma is recognized as a precancerous lesion of colorectal cancer, and the serrated pathway is considered as an important pathway that can independently develop into colorectal cancer. However, little is known about the related risk factors of carcinogenesis of serrated adenoma. The purpose of this study was to analyze the distribution characteristics and potential malignant factors of serrated adenoma in the colon and rectum. Methods: A retrospective case-control study was conducted to collect the clinical data of patients with serrated adenoma who underwent colonoscopy and were pathologically diagnosed in the Cancer Hospital of Chinese Academy of Medical Sciences from April 2017 to July 2019, and exclude patients with two or more pathological types of lesions. The clinical characteristics of serrated adenoma were summarized, and univariate and logistic multivariate regression analysis was conducted to explore the influencing factors for serrated adenoma to develop malignant transformation. Results: Among 28 730 patients undergoing colonoscopy, 311 (1.08%) were found with 372 serrated adenomas, among which 22 (5.9%) were sessile serrated adenomas/polyps, 84 (22.6%) were traditional serrated adenomas, and 266 (71.5%) were unclassified serrated adenomas according to WHO classification. The pathological results showed that 106 (28.5%) lesions were non-dysplasia, 228 (61.3%) lesions were low grade intraepithelial neoplasia, and 38 (10.2%) lesions were high grade intraepithelial neoplasia or cancer. There were 204 (54.8%) lesions with long-axis diameter <10 mm and 168 (45.2%) lesions with length long-axis ≥ 10 mm. 238 (64.0%) lesions were found in the left side colon and rectum and 134 (36.0%) lesions in the right side colon. Gross classification under endoscopy: 16 flat type lesions (4.3%), 174 sessile lesions (46.8%), 117 semi-pedunculated lesions (31.5%), 59 pedunculated lesions (15.9%). Narrow-band imaging international colorectal endoscopic (NICE) classification: 85 (22.8%) type I lesions, 280 (75.3%) type II lesions, 4 (1.1%) type III lesions. Univariate analysis showed that lesion size, lesion location, lesion site and different WHO classifications were associated with malignant transformation of colorectal serrated adenoma (all P<0.05). For the serrated adenomas with different NICE classifications, there were statistically significant differences in the distribution of malignant lesions among groups (P=0.001). Multivariate analysis showed that the long-axis diameter of the lesion ≥10 mm (OR=6.699, 95% CI: 2.843-15.786) and the lesion locating in the left side colorectum (OR=2.657, 95% CI: 1.042-6.775) were independent risk factors for malignant transformation. Conclusions: Serrated adenomas mainly locate in the left side colon and rectum, and are prone to malignant transformation when the lesions are ≥10 mm in long-axis diameter or left-sided.

Validation of serrated polyps (SPs) in Swedish pathology registers

Background

Little is known about the natural history of serrated polyps (SPs), partly due to the lack of large-scale epidemiologic data. In this study, we examined the validity of SP identification according to SNOMED (Systematised Nomenclature of Medicine) codes and free text from colorectal histopathology reports.

Methods

Through the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, we retrieved data on SPs from all pathology departments in Sweden in 2015–2017 by using SNOMED codes and free-text search in colorectal histopathology reports. Randomly selected individuals with a histopathology report of SPs were validated against patient charts using a structured, retrospective review.

Results

SPs were confirmed in 101/106 individuals with a histopathology report of SPs, yielding a positive predictive value (PPV) of 95% (95%CI = 89–98%). By year of diagnosis, the PPV was 89% (95%CI = 69–97%), 96% (95%CI = 81–99%) and 97% (95%CI = 89–99%) for individuals diagnosed before 2001 (n = 19), between 2001 and 2010 (n = 26) and after 2010 (n = 61), respectively. According to search method, the PPV for individuals identified by SNOMED codes was 100% (95%CI = 93–100%), and 93% (95%CI = 86–97%) using free-text search. Recorded location (colon vs. rectum) was correct in 94% of all SP histopathology reports (95%CI = 84–98%) identified by SNOMED codes. Individuals with SPs were classified into hyperplastic polyps (n = 34; 32%), traditional serrated adenomas (n = 3; 3%), sessile serrated adenomas/polyps (SSA/Ps) (n = 70; 66%), unspecified SPs (n = 3, 3%), and false positive SPs (n = 5, 5%). For individuals identified by SNOMED codes, SSA/Ps were confirmed in 49/52 individuals, resulting in a PPV of 94% (95%CI: 84–98%). In total, 57% had ≥2 polyps (1: n = 44, 2–3: n = 33 and ≥ 4: n = 27). Some 46% of SPs (n = 71) originated from the proximal colon and 24% were ≥ 10 mm in size (n = 37). Heredity for colorectal cancer, intestinal polyposis syndromes, or both was reported in seven individuals (7%). Common comorbidities included diverticulosis (n = 45, 42%), colorectal cancer (n = 19, 18%), and inflammatory bowel disease (n = 10, 9%).

Conclusion

Colorectal histopathology reports are a reliable data source to identify individuals with SPs.

Significant Variation in the Detection Rates of Proximal Serrated Polyps Among Academic Gastroenterologists, Community Gastroenterologists, and Colorectal Surgeons in a Single Tertiary Care Center

INTRODUCTION

Recent studies have demonstrated that the protective effect of colonoscopy against colorectal cancer is lower in the proximal colon. Proximal serrated polyps, including sessile serrated adenomas and proximal hyperplastic polyps, can be frequently missed and pose a risk of interval cancers.

AIM

To investigate the overall adenoma detection rate (ADR) and the proximal serrated polyp detection rate (PSPDR) among academic gastroenterologists, community gastroenterologists, and colorectal surgeons from a single institution, all of whom have received formal training in colonoscopy during their fellowship.

METHODS

All complete screening colonoscopies for patients aged 50 or older with a good to excellent bowel preparation performed by different endoscopists at Medstar Washington Hospital Center (Washington, DC) from July 2015 to December 2017 were reviewed. Pathology reports of the resected polyps were manually reviewed.

RESULTS

A total of 2850 screening colonoscopies meeting the inclusion criteria were performed by 18 endoscopists (6 academic, 7 community, and 5 colorectal surgeons). There was no significant difference in the mean ADR among the three groups of endoscopists: academic gastroenterologists, community gastroenterologists, and colorectal surgeons (40.3% vs 36.0% vs 39.6%, respectively). However, academic gastroenterologists had a significantly higher PSPDR compared to community gastroenterologists or colorectal surgeons (12.3% vs 5.4% vs 4.5%, respectively, ANOVA p = 0.006).

CONCLUSION

Our novel data show that academic gastroenterologists had a significantly higher PSPDR compared to community gastroenterologists or colorectal surgeons despite a comparable overall ADR among the three groups. PSPDR may be considered as an important quality indicator for colonoscopy, apart from ADR.

Low detection rate of advanced neoplasia within 5 years after polypectomy of small serrated adenoma

AIM

Patients with small serrated adenomas (SAs) (<10 mm) often undergo surveillance colonoscopy before the routine recommended time. We aimed to determine the appropriate surveillance intervals following polypectomy of small SAs for symptomatic patients.

METHOD

We retrospectively reviewed the data of 638 patients, including 122 cases and 516 controls. Subjects in the case group had small SAs at baseline colonoscopy, including sessile SA/polyps and traditional SAs, while subjects in the control group had negative findings. All patients underwent at least one surveillance colonoscopy during the following 5 years.

RESULTS

There was no significant difference in the incidence rate of advanced neoplasia between the two groups over a 5-year duration (3.6% vs 2.6%, p=0.455). Moreover, both groups also showed a low prevalence of SA formation over 1-5 years (3.6% vs 1.0%, p=0.145). Patients with baseline SA tended to undergo the first surveillance colonoscopy earlier than those without adenoma (≤1 year vs 1 to ≤3 years). Seventy-one (11.1%) of the total included subjects underwent inadequate initial colonoscopy, and 30 (42.3%) underwent early surveillance of adenoma formation within 1 year. Patients with a family history of colorectal cancer (OR 4.69, 95% CI 1.48 to 14.71, p=0.017) or inadequate baseline colonoscopy (OR 3.17, 95% CI 1.202 to 8.409, p=0.035) were at a higher risk of metachronous adenoma formation during the surveillance period.

CONCLUSION

Patients with small SAs at baseline gain little benefit from follow-up of colonoscopy within 5 years after complete polypectomy.

Silencing the GUCA2A-GUCY2C tumor suppressor axis in CIN, serrated, and MSI colorectal neoplasia

Colorectal cancers (CRCs) initiate through distinct mutations, including in APC pathway components leading to tubular adenomas (TAs); in BRAF, with epigenetic silencing of CDX2, leading to serrated adenomas (SAs); and in the DNA mismatch repair machinery driving microsatellite instability (MSI). Transformation through the APC pathway involves loss of the hormone GUCA2A that silences the tumor-suppressing receptor GUCY2C. Indeed, oral hormone replacement is an emerging strategy to reactivate GUCY2C and prevent CRC initiation and progression. Moreover, retained expression by tumors arising from TAs has established GUCY2C as a diagnostic and therapeutic target to prevent and treat metastatic CRC. Here, we defined the potential role of the GUCA2A-GUCY2C axis and its suitability as a target in tumors arising through the SA and MSI pathways. GUCA2A hormone expression was eliminated in TAs, SAs, and MSI tumors compared to their corresponding normal adjacent tissues. In contrast to the hormone, the tumor-suppressing receptor GUCY2C was retained in TA and MSI tumors. Surprisingly, GUCY2C expression was nearly eliminated in SAs, reflecting loss of the transcription factor CDX2. Changes in the GUCA2A-GUCY2C axis in human SAs and MSI tumors were precisely recapitulated in genetic mouse models. These data reveal the possibility of GUCA2A loss silencing GUCY2C in the pathophysiology of, and oral hormone replacement to restore GUCY2C signaling to prevent, MSI tumors. Also, they highlight the potential for targeting GUCY2C to prevent and treat metastases arising from TA and MSI tumors. In contrast, loss of GUCY2C excludes patients with SAs as candidates for GUCY2C-based prevention and therapy.

Jejunal Serrated Adenoma Diagnosed and Treated by Double-Balloon Enteroscopy

Serrated polyps are most commonly located in the colorectum and have been well recognized as an important precursor lesion for colorectal cancer. Serrated adenoma in the small intestine has been reported more rarely but may represent a distinct morphological and biological subtype with malignant potential. Here, we present the case of a 65-year-old female who underwent double-balloon enteroscopy due to obscure gastrointestinal bleeding. A polyp sized 3.5 × 2.0 cm with a long pedicle in the jejunum, located 50 cm distal to the Treitz ligament, was detected. Endoscopic mucosal resection was done. The pathological results revealed a traditional serrated adenoma sized 3.5 × 2.2 cm.

Clinical outcomes of surveillance colonoscopy for patients with sessile serrated adenoma

Background/Aims

Sessile serrated adenomas (SSAs) are known to be precursors of colorectal cancer (CRC). The proper interval of follow-up colonoscopy for SSAs is still being debated. We sought to determine the proper interval of colonoscopy surveillance in patients diagnosed with SSAs in South Korea.

Methods

We retrospectively reviewed the medical records of patients diagnosed with SSAs who received 1 or more follow-up colonoscopies. The information reviewed included patient baseline characteristics, SSA characteristics, and colonoscopy information.

Results

From January 2007 to December 2011, 152 SSAs and 8 synchronous adenocarcinomas were identified in 138 patients. The mean age of the patients was 62.2 years and 60.1% patients were men. SSAs were located in the right colon (i.e., from the cecum to the hepatic flexure) in 68.4% patients. At the first follow-up, 27 SSAs were identified in 138 patients (right colon, 66.7%). At the second follow-up, 6 SSAs were identified in 65 patients (right colon, 66.7%). At the 3rd and 4th follow-up, 21 and 11 patients underwent colonoscopy, respectively, and no SSAs were detected. The total mean follow-up duration was 33.9 months. The mean size of SSAs was 8.1±5.0 mm. SSAs were most commonly found in the right colon (126/185, 68.1%). During annual follow-up colonoscopy surveillance, no cancer was detected.

Conclusions

Annual colonoscopy surveillance is not necessary for identifying new CRCs in all patients diagnosed with SSAs. In addition, the right colon should be examined more carefully because SSAs occur more frequently in the right colon during initial and follow-up colonoscopies.

Slow-Growing Early Adenocarcinoma Arising from Traditional Serrated Adenoma in the Duodenum

Serrated polyps are classified into 3 distinct types: hyperplastic polyp, sessile serrated adenoma, or transitional serrated adenoma. A serrated adenoma is a precursor lesion for colorectal carcinoma. Serrated polyps are commonly found in the colorectum but have rarely been described in other parts of the gastrointestinal tract. Serrated adenomas in the small intestine may represent aggressive lesions with high malignant potential, according to some reports. A 66-year-old man with no significant medical history underwent esophagogastroduodenoscopy (EGD) for general examination. He had a 1-cm sized, Yamada type IV polyp, with focal white patch in the second portion of the duodenum. The biopsy result revealed gastric metaplasia and chronic inflammation. He wanted regular follow -up examinations. The follow-up EGDs were done every year. There were no changes in the shape and size of the polyp. The pathologic findings were unchanged. Then, he underwent EGD for general medical check-up again 5 years after the first detection. The size of the polyp was slightly increased. The biopsy result revealed serrated polyp, unclassified. Endoscopic mucosal resection was done. The pathologic result revealed a 0.8 × 0.5-cm sized, well differentiated tubular adenocarcinoma. Carcinomas are multifocally spread on the traditional serrated adenoma, and the proportion of the adenocarcinoma component is approximately 50%. The tumor had invaded the lamina propria but confined to the mucosa. The resection margins were negative, and no lymphovascular invasion or perineural invasion was seen. Abdominal pelvic computed tomography and positron emission tomography showed no other solid organ involvement or metastasis. Surveillance follow-up EGDs were done after 3 months and 1 year. There was no evidence of recurrence.

Epidemiology of Colorectal Adenomas and Histopathological Assessment of Endoscopic Specimens in the Colorectum

BACKGROUND

Colorectal cancer is one of the most frequently observed neoplasms in the world. It develops from intraepithelial neoplasia of the colorectal mucosa, and these precursor lesions are also known as adenoma. As the precursor lesion is known and can be detected easily, efficient screening strategies are available for a reliable prevention of colorectal adenocarcinoma, e.g. by colonoscopy.

METHODS

Literature databases (PubMed) were searched selectively for the keywords 'colorectal adenoma', 'epidemiology', and 'resection techniques'. The results are presented in the following text, also taking into account our own experience and the current S3 guidelines.

RESULTS

Endoscopic resection samples are one of the specimens most frequently assessed by pathologists. Therefore, gastroenterologists expect standardized and well-structured pathology reports, stating relevant information concerning the removed lesions and recommendations for clinical management. These aspects are summarized in the evidence-based S3 guideline.

CONCLUSION

As a consequence of colorectal adenoma resection during screening procedures, the carcinoma incidence is decreasing. For further advancements in successful prevention, knowledge of different precursor lesions (conventional adenoma, serrated adenoma) is important, but also structured communication between the different disciplines engaged in colorectal cancer screening.

Three Colon Adenocarcinomas Arising in a Patient with Serrated Polyposis Syndrome: Case Report and Review of the Literature

Background

Serrated polyposis syndrome (SPS) is a rare entity mainly concerning the 6th decade of life and which is characterized by the presence of multiple large hyperplastic polyps, sessile serrated adenomas, and adenomas within the colon.

Case Report

We describe the case of a SPS patient with 3 synchronous adenocarcinomas. The morphologic features of serrated colorectal lesions, their characteristic molecular alterations, and their role in colorectal cancer development are discussed herein.

Conclusion

Our findings suggest that SPS is a rare condition with an increased risk for colon cancer. Patients suffering from SPS should have regular colonoscopic surveillance, and perhaps those with numerous dysplastic hyperplastic polyps should be treated with colectomy.

Prevalence and characteristics of serrated lesions of the colorectum in Italy: A multicentre prospective cohort study

BACKGROUND

Serrated lesions are recognized as important contributors to colorectal cancer incidence. We aimed to prospectively assess the prevalence of serrated lesions and identify potential predictors of these lesions during colonoscopy in an Italian population.

METHODS

Prospective cross sectional study involving 8 endoscopy units from February 1st to July 31st 2012.

RESULTS

Out of 2468 colonoscopies, 886 precancerous lesions were detected in 567 patients. Of these, 173 SELs were diagnosed in 148 patients (140 serrated/hyperplastic polyps and 33 serrated adenomas). Prevalence was 7% (173/2468). Serrated lesions accounted for 19.5% of all precancerous lesions. Serrated polyps were prevalent in the left colon (42.1%) and serrated adenomas in the proximal colon (54.5%). Independent clinical predictors of serrated lesions were patient age (OR 0.98 [0.97-1.00]) and post-polypectomy surveillance (OR 1.87 [1.24-2.82]). Endoscopic predictors were right colon location (OR 2.65 [1.63-4.30] vs. rectum; and 1.53 [1.03-2.26] vs. left colon), polypoid shape (OR 0.41 [027-0.64]) and size <6 mm (OR 0.49 [0.33-0.72] vs. 6-10 mm; and 0.14 [0.07-0.28] vs. >10 mm). There was no independent predictor of serrated adenoma.

CONCLUSION

In our Italian study population, the prevalence of colorectal serrated lesions was 7%. Their diagnosis is associated with younger age and surveillance colonoscopy, right-sided colorectal location, non-polypoid shape and size <6 mm.

Sessile serrated adenoma: from identification to resection

Until the past two decades, almost all colorectal polyps were divided into two main groups: hyperplastic polyps and adenomas. Sessile serrated adenomas presented endoscopic, pathological and molecular profiles distinct from others polyps. Previously under-diagnosed, physicians now identified sessile serrated adenomas. The serrated neoplastic pathway is accounting for up to one-third of all sporadic colorectal cancers and sessile serrated adenomas have been identified as the main precursor lesions in serrated carcinogenesis. By analogy with the adenoma-adenocarcinoma sequence, the sessile serrated adenomas-adenocarcinoma sequence, has been identified. The development of endoscopic resection techniques permits the consideration of a non-surgical approach as the first option regardless of the size of the lesion. Sessile serrated adenoma warrants the watchfulness of physicians and requires an optimal quality of the colonoscopy procedure, a thorough evaluation of the lesion, an adequate endoscopic resection and follow-up colonoscopies in accordance with sessile serrated adenomas guidelines. We herein present a review on sessile serrated adenomas focusing on their pathological specificities, epidemiology, treatment modalities and follow-up.

Endoscopic diagnosis of sessile serrated adenoma

Sessile serrated adenoma (SSA) is a special type of serrated adenoma, and recent studies have found that SSA has a malignant potential, progresses quickly and is closely related to right-sided colorectal cancer. SSA is usually located in the proximal colon, which is flat and sessile, and for this reason, SSA is difficult to find by conventional endoscopy and has a high rate of missed diagnosis. There is currently an urgent need to develop new endoscopic technologies to raise the diagnosis rate. In this paper, we will review recent progress in the diagnosis of sessile serrated adenoma using new endoscopic technologies.

Colonoscopic characteristics of serrated adenomas

AIM: To investigate the morphologic features of serrated adenomas (SA) by regular high-resolution colonoscopy with narrow band imaging (NBI).

METHODS: A retrospective analysis was performed of the imaging data for patients with colorectal SA who underwent colonoscopy between March 2010 and June 2013. A comparison of colonoscopic features was made between SA and hyperplastic polyps (HP) with comparable predicted diameter.

RESULTS: A total of 50 SA from 35 patients and 50 HP from 42 patients were included. More SA were located in the right colon than in the left colon (48% vs 36%, P > 0.05). Type IIa or laterally spreading tumors (LST) were more commonly seen in SA (P = 0.019) and II-O pit pattern was more commonly seen in HP (P = 0.000). SA more frequently showed the features of vague margins, irregular shape, cloud-like surface and dark bleeding spots in crypts (all P < 0.001). The sensitivities of II-O pit pattern, cloud-like surface, indistinct border, irregular shape and dark bleeding spots in the crypts for predicting SA were 44%, 92%, 30%, 66% and 76%, respectively, and the specificities were 98%, 98%, 98%, 94% and 92%, respectively. The sensitivity and specificity of the presence of three or more above characteristics for predicting SA were 80% and 100%, respectively.

CONCLUSION: SA have certain colonoscopic features, which can aid in differentiating SA from HP.

Traditional serrated adenoma of the colorectum: clinicopathologic implications and endoscopic findings of the precursor lesions

OBJECTIVES

To investigate the clinicopathologic and endoscopic features of precursor lesions associated with traditional serrated adenomas (TSAs).

METHODS

Mutation studies for BRAF, KRAS, PIK3CA, and EGFR and immunohistochemical staining for Ki-67 were performed on 107 TSAs from 104 patients.

RESULTS

Nondysplastic hyperplastic polyp (HP) or sessile serrated adenoma/polyp (SSA/P) precursor lesions were found in 56 (52.3%) TSAs, among which 32 (57.1%) cases showed a flat-elevated lesion with a type II pit pattern during endoscopy. TSAs with an SSA/P precursor lesion were usually found in the proximal colon, while TSAs with an HP or with no precursor lesion were mainly located in the distal colon and rectum (P < .001). TSAs with a precursor lesion showed a lower frequency of conventional epithelial dysplasia and KRAS mutation as well as a higher frequency of BRAF mutation compared with those with no precursor lesion (P = .002, P < .001, and P < .001, respectively).

CONCLUSIONS

A significant proportion of HP or SSA/P precursor lesions accompanied by TSAs can be detected by endoscopy based on both their flat-elevated growth and type II pit patterns. The heterogeneity of TSAs in terms of clinicopathologic and molecular features correlated with the status or type of precursor lesions.

Cronkhite-Canada syndrome associated with serrated adenoma and malignant polyp: a case report and a literature review of 13 cronkhite-Canada syndrome cases in Korea

Cronkhite-Canada syndrome (CCS) is a rare nonfamilial polyposis syndrome characterized by epithelial disturbances both in the gastrointestinal tract and in the epidermis. The pathologic finding of the polyp is usually a hamartomatous polyp of the juvenile type; however, the possibility of serrated adenoma associated malignant neoplasm was reported in some Japanese cases. Up till now in South Korea, 13 CCS cases have been reported, but there was no case accompanied by the colon cancer. We report the first case of CCS associated with malignant colon polyp and serrated adenoma in Korea. A 72-year-old male patient who complained of diarrhea and weight loss was presented with both hands and feet nail dystrophy, hyperpigmentation, and alopecia. Endoscopic examination showed numerous hamartomatous polyps from the stomach to the colon. The pathologic results confirmed colon cancer and serrated adenoma. Helicobacter pylori eradication and prednisolone was used. Thus, the authors report this case along with a literature review.

Evaluation of magnifying colonoscopy in the diagnosis of serrated polyps

AIM

To elucidate the colonoscopic features of serrated lesions of the colorectum using magnifying colonoscopy.

METHODS

Broad division of serrated lesions of the colorectum into hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenomas/polyps (SSA/Ps) has been proposed on the basis of recent molecular biological studies. However, few reports have examined the colonoscopic features of these divisions, including magnified colonoscopic findings. This study examined 118 lesions excised in our hospital as suspected serrated lesions after magnified observation between January 2008 and September 2011. Patient characteristics (sex, age), conventional colonoscopic findings (location, size, morphology, color, mucin) and magnified colonoscopic findings (pit pattern diagnosis) were interpreted by five colonoscopists with experience in over 1000 colonoscopies, and were compared with histopathological diagnoses. The pit patterns were categorized according to Kudo's classification, but a more detailed investigation was also performed using the subclassification [type II-Open (type II-O), type II-Long (type II-L), or type IV-Serrated (type IV-S)] proposed by Kimura T and Yamano H.

RESULTS

Lesions comprised 23 HPs (23/118: 19.5%), 39 TSAs (39/118: 33.1%: with cancer in one case), 50 SSA/Ps (50/118: 42.4%: complicated with cancer in three cases), and six others (6/118: 5.1%). We excluded six others, including three regular adenomas, one hamartoma, one inflammatory polyp, and one juvenile polyp for further analysis. Conventional colonoscopy showed that SSA/Ps were characterized as larger in diameter than TSAs and HPs (SSA/P vs HP, 13.62 ± 8.62 mm vs 7.74 ± 3.24 mm, P < 0.001; SSA/Ps vs TSA, 13.62 ± 8.62 mm vs 9.89 ± 5.73 mm, P < 0.01); common in the right side of the colon [HPs, 30.4% (7/23): TSAs, 20.5% (8/39): SSA/P, 84.0% (42/50), P < 0.001]; flat-elevated lesion [HPs, 30.4% (7/23): TSAs, 5.1% (2/39): SSA/Ps, 90.0% (45/50), P < 0.001]; normal-colored or pale imucosa [HPs, 34.8% (8/23): TSAs, 10.3% (4/39): SSA/Ps, 80% (40/50), P < 0.001]; and with large amounts of mucin [HPs, 21.7% (5/23): TSAs, 17.9% (7/39): SSA/Ps, 72.0% (36/50), P < 0.001]. In magnified colonoscopic findings, 17 lesions showed either type II pit pattern alone or partial type II pit pattern as the basic architecture, with 14 HPs (14/17, 70.0%) and 3 SSA/Ps. Magnified colonoscopy showed the type II-O pit pattern as characteristic of SSA/Ps [sensitivity 83.7% (41/49), specificity 85.7% (54/63)]. Cancer was also present in three lesions, in all of which a type VI pit pattern was also present within the same lesion. There were four HPs and four TSAs each. The type IV-S pit pattern was characteristic of TSAs [sensitivity 96.7% (30/31), specificity 89.9% (72/81)]. Cancer was present in one lesion, in which a type VI pit pattern was also present within the same lesion. In our study, serrated lesions of the colorectum also possessed the features described in previous reports of conventional colonoscopic findings. The pit pattern diagnosis using magnifying colonoscopy, particularly magnified colonoscopic findings using subclassifications of surface architecture, reflected the pathological characteristics of SSA/Ps and TSAs, and will be useful for colonoscopic diagnosis.

CONCLUSION

We suggest that this system could be a good diagnostic tool for SSA/Ps using magnifying colonoscopy.

Protein expression and gene mutations of β-catenin in colorectal serrated adenoma

AIM: To investigate the protein expression of β-catenin and the mutations in exon 3 of the β-catenin gene in colorectal traditional serrated adenoma (TSA), conventional adenoma (TA/VTA) and colorectal carcinoma (CRC), and to analyze the relationship between β-catenin expression and the carcinogenesis of TSA.

METHODS: Thirty TSA specimens, 20 TA/VTA specimens, and 21 CRC specimens were collected. The protein expression of β-catenin was detected by immunohistochemical staining. β-catenin exon 3 mutations were detected by sequencing DNA from β-catenin-positive TSA (8 cases), TA (6 cases), VTA (5 cases), and CRC (10 cases) specimens.

RESULTS: There are significant differences in the positive rates of β-catenin expression among TSA, TA/VTA and CRC (P = 0.000). No significant difference was noted in the positive rate of β-catenin expression between TSA and TA/VTA (P > 0.05) though a significant difference was found between TSA and CRC (P < 0.05). The degree of dysplasia in both TSA and TA/VTA was correlated with the positive rate of β-catenin expression (TSA: P < 0.01; TA/VTA: P < 0.05). No β-catenin exon 3 mutations were detected in TSA, TA/VTA or CRC.

CONCLUSION: Abnormal expression of β-catenin is related to the degree of dysplasia in TSA. β-catenin may play a role in the neoplastic progression of TSA.

Serrated Adenoma of Gastric Antrum: Alteration of Mucin Expression Profile and its Role in Carcinogenesis

Serrated adenomas usually occur in colon, the gastric localization is extremely rare. These polyps have their own carcinogenetic pathway with microsatellite instability. In this report, we present a serrated adenoma localized in gastric antrum with four control endoscopies and biopsies. Immunohistochemical panel of MUC1, MUC2, MUC5AC, and MUC6 was applied to the biopsies. Serrated component, MUC 2 expression increased but goblet cells and MUC5AC expression decreased in follow-up biopsies. This lesion probably was originated from a stem cell that had the potential of differentiation in gastric and intestinal way. This might result an incomplete metaplasia for both colon and stomach. Such lesions which originate from either colon or gastric mucosa may be precancerous and their carcinogenetic pathway may not represent its original organ.

Serrated neoplasia of the colorectum

Serrated polyps of the colorectum form a group of related lesions which include aberrant crypt foci (ACF), conventional hyperplastic polyps, mixed (admixed) polyps, serrated adenomas and sessile serrated adenomas. In recent years the molecular differences between these morphologically similar lesions have been highlighted, and their differing biological potential has been realised. In particular, the sessile serrated adenoma has become recognised as the precursor lesion to a group of sporadic colorectal carcinomas characterised by morphological and molecular features distinct from conventional adenomas. These recent findings have challenged the long held paradigm that all colorectal carcinomas arise via the traditional adenoma-carcinoma sequence. In addition, they present a major challenge for the early detection and management of colorectal cancer, which is no longer regarded as a homogeneous entity.

Colorectal carcinogenesis: Road maps to cancer

This review explores the chief genetic and epigenetic events that promote pathological progression in colorectal carcinogenesis. This article discusses the molecular and pathological basis for classifying colorectal neoplasia into suppressor, mutator and methylator pathways. These differing mechanisms of genomic instability are associated with specific cancer characteristics, and may provide the opportunity for more effective prevention and surveillance strategies in the future. This is the first review in a series of five topics outlining important and developing aspects of colorectal cancer.

Hyperplastic polyposis associated with two asynchronous colon cancers

We report a patient with hyperplastic polyposis who had two asynchronous colon cancers, a combined adenoma-hyperplastic polyp, a serrated adenoma, and tubular adenomas. Hyperplastic polyposis is thought to be a precancerous lesion; and adenocarcinoma arises from hyperplastic polyposis through the hyperplastic polyp-adenoma-carcinoma sequence. Most polyps in patients with hyperplastic polyposis present as bland-looking hyperplastic polyps, which are regarded as non-neoplastic lesions; however, the risk of malignancy should not be underestimated. In patients with multiple hyperplastic polyps, hyperplastic polyposis should be identified and followed up carefully in order to detect malignant transformation in the early stage.

Clinico-pathological aspects of colorectal serrated adenomas

AIM: To study the association of colorectal serrated adenomas (SAs) with invasive carcinoma, local recurrence, synchronicity and metachronicity of lesions.

METHODS: A total of 4536 polyps from 1096 patients over an eight-year period (1987-1995) were retrospectively examined. Adenomas showing at least 50% of serrated architecture were called SAs by three reviewing pathologists.

RESULTS: Ninety-one (2%) of all polyps were called SAs, which were found in 46 patients. Invasive carcinomas were seen in 3 out of 46 (6.4%) patients, of whom one was a case of familial adenomatous polyposis (FAP). A male preponderance was noted and features of a mild degree of dysplasia were seen in majority (n=75, 83%) of serrated adenomas. Follow-up ranged 1-12 years with a mean time of 5.75 years. Recurrences of SAs were seen in 3 (6.4%) cases, synchronous SAs in 16 (34.8%) cases and metachronous SAs in 9 (19.6%) cases.

CONCLUSION: Invasive carcinoma arising in serrated adenoma is rare, accounting for 2 (4.3%) cases studied in this series.